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Darby Weaver

UDLD versus UDLD Aggressive by Darby Weaver

43 posts in this topic

Configuring UniDirectional Link Detection:

 

It is considered a best practice to configure UDLD in "aggressive mode".

 

What does UDLD do?

 

UDLD is designed to mitigate fault conditions on both Ethernet and Fiber interfaces. It does this shutting down the interfaces that may be either miswired or where a fault has occurred and then putting those ports in Err-Disable Mode.

 

UDLD is a Layer 2 Protocol. UDLD is typically used to in combination with Layer 1 autonegotiation features. UDLD validates the physical and logical link's integrity and when there is a detected fault it will put the port into Err-Disable Mode. UDLD establishes and maintains a cache that is populated by the status of each directly connected neighbor where UDLD is enabled and in use. UDLD learns about neighbors using a UDLD echo aka hello messages.

 

 

What is UDLD Agressive Mode?

 

UDLD Aggressive Mode is an enhanced operational mode of UDLD that actually attempts to re-establish the connection with the neighbor whenever a failure is detected. UDLD Aggressive will work to detect when one side of the link remains up and the other side has gone down. After 8 failed retries, UDLD Aggressive will transition the port to Err-Disabled Mode and generate a Syslog Message.

 

How's that for service with a smile and verification?

 

Cisco has recommended configuring UDLD Agressive versus only UDLD Mode on point-to-point FE/GE links and even getting a little more agressive and setting the message interval to 15 seconds. UDLD is disabled by default globally.

 

Examples to follow: I would not want to leave you hanging.

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Step 1 Setting up our Debug Commands on a Cisco 3550 Catalyst Switch:

 

Sw4#debug udld ?

events UDLD events

packets UDLD packets

registries UDLD registry events

 

Sw4#debug udld events ?

<cr>

 

Sw4#debug udld events

UDLD events debugging is on

Sw4#debug udld packets ?

<cr>

 

Sw4#debug udld packets

UDLD packets debugging is on

Sw4#debug udld registries

UDLD registries debugging is on

 

 

 

We need to see the magic - that's my point...

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Step 2 Limit the debug to what we care about aka Conditional Debugging.

 

Sw4#sh cdp nei

Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge

S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

 

Device ID Local Intrfce Holdtme Capability Platform Port ID

Sw1 Fas 0/22 129 R S I WS-C3550- Fas 0/22

Sw1 Fas 0/21 129 R S I WS-C3550- Fas 0/21

Sw2 Fas 0/20 126 R S I WS-C3550- Fas 0/20

Sw2 Fas 0/19 126 R S I WS-C3550- Fas 0/19

Sw3 Fas 0/24 126 R S I WS-C3550- Fas 0/24

Sw3 Fas 0/23 126 R S I WS-C3550- Fas 0/23

 

 

Sw4#debug int f0/24

Condition 1 set

Sw4#

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Step 3: What does "show udld" look like before we configure UDLD globally?

 

 

 

Sw4(config)#do sh udld

 

Interface Fa0/1

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/2

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/3

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/4

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/5

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/6

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/7

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/8

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/9

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/10

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/11

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/12

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/13

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/14

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/15

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/16

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/17

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/18

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/19

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/20

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/21

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/22

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/23

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/24

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Gi0/1

---

Port enable administrative configuration setting: Follows device default

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Gi0/2

---

Port enable administrative configuration setting: Follows device default

Port enable operational state: Disabled

Current bidirectional state: Unknown

Sw4(config)#

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Step 4: Let's equalize where we on on our neighbor Sw3 on Fa0/24

 

Check this out... looks like got activity?

 

 

Sw4#sh udld filter ?

<0-1> Filter interface number

Sw4#sh udld neig

Port Device Name Device ID Port ID Neighbor State

---- ----------- --------- ------- --------------

Sw4#

*Mar 6 22:52:15.088: Checking if multiple neighbors (Fa0/24)

*Mar 6 22:52:15.088: No entries in cache: no neighbors (Fa0/24)

*Mar 6 22:52:15.088: Checking if multiple neighbors (Fa0/24)

*Mar 6 22:52:15.088: No entries in cache: no neighbors (Fa0/24)

Sw4#

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Alert:

 

I read that UDLD was disabled by default. That's what it said... I repeated it... and now Truth by Debug says differently:

 

Sw3#debug udld events

UDLD events debugging is on

Sw3#debug udld packets

UDLD packets debugging is on

Sw3#debug udld p

2d14h: UDLD send probe message, flags = rec_timeout (Fa0/10)

2d14h: P (Fa0/10)

Sw3#debug udld registries

UDLD registries debugging is on

Sw3#

2d14h: UDLD send probe message, flags = rec_timeout (Fa0/10)

2d14h: P (Fa0/10)

Sw3#

 

 

 

Why is it probing?

 

Looks a little agressive to me already:

 

Sw3#sh udld nei

Port Device Name Device ID Port ID Neighbor State

---- ----------- --------- ------- --------------

Sw3#

2d14h: udld_ether_macaddr called

2d14h: Checking if multiple neighbors (Fa0/24)

2d14h: No entries in cache: no neighbors (Fa0/24)

2d14h: Checking if multiple neighbors (Fa0/24)

2d14h: No entries in cache: no neighbors (Fa0/24)

Sw3#sh udld ?

Async Async interface

Auto-Template Auto-Template interface

BVI Bridge-Group Virtual Interface

CTunnel CTunnel interface

Dialer Dialer interface

EsconPhy ESCON interface

FastEthernet FastEthernet IEEE 802.3

Filter Filter interface

Filtergroup Filter Group interface

GigabitEthernet GigabitEthernet IEEE 802.3z

Group-Async Async Group interface

GroupVI Group Virtual interface

Lex Lex interface

Loopback Loopback interface

Multilink Multilink-group interface

Null Null interface

Port-channel Ethernet Channel of interfaces

Portgroup Portgroup interface

Pos-channel POS Channel of interfaces

SYSCLOCK Telecom-Bus Clock Controller

Tunnel Tunnel interface

Vif PGM Multicast Host interface

Virtual-Template Virtual Template interface

Virtual-TokenRing Virtual TokenRing

Vlan Catalyst Vlans

fcpa Fiber Channel

neighbors UDLD Neighbors Summary

voaBypassIn VOA-Bypass-In interface

voaBypassOut VOA-Bypass-Out interface

voaFilterIn VOA-Filter-In interface

voaFilterOut VOA-Filter-Out interface

voaIn VOA-In interface

voaOut VOA-Out interface

| Output modifiers

<cr>

 

Sw3#sh udld

2d14h: udld_ether_macaddr called

Sw3#sh udld F

Sw3#sh udld F0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

Sw3#

2d14h: udld_ether_macaddr called

2d14h: Checking if multiple neighbors (Fa0/24)

2d14h: No entries in cache: no neighbors (Fa0/24)

2d14h: Checking if multiple neighbors (Fa0/24)

2d14h: No entries in cache: no neighbors (Fa0/24)

Sw3#

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Now let's enable UDLD:

 

 

Sw3#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Sw3(config)#

2d14h: udld_ether_macaddr called

Sw3(config)#udld enable

Sw3(config)#

2d14h: udld_ether_macaddr called

Sw3(config)#

TS4#10

[Resuming connection 10 to s4 ... ]

 

Sw4#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Sw4(config)#udld en

Sw4(config)#

 

 

Sw4#sh cdp nei

Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge

S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

 

Device ID Local Intrfce Holdtme Capability Platform Port ID

Sw1 Fas 0/22 142 R S I WS-C3550- Fas 0/22

Sw1 Fas 0/21 142 R S I WS-C3550- Fas 0/21

Sw2 Fas 0/20 139 R S I WS-C3550- Fas 0/20

Sw2 Fas 0/19 139 R S I WS-C3550- Fas 0/19

Sw3 Fas 0/24 139 R S I WS-C3550- Fas 0/24

Sw3 Fas 0/23 139 R S I WS-C3550- Fas 0/23

Sw4#sh udld ?

Async Async interface

Auto-Template Auto-Template interface

BVI Bridge-Group Virtual Interface

CTunnel CTunnel interface

Dialer Dialer interface

EsconPhy ESCON interface

FastEthernet FastEthernet IEEE 802.3

Filter Filter interface

Filtergroup Filter Group interface

GigabitEthernet GigabitEthernet IEEE 802.3z

Group-Async Async Group interface

GroupVI Group Virtual interface

Lex Lex interface

Loopback Loopback interface

Multilink Multilink-group interface

Null Null interface

Port-channel Ethernet Channel of interfaces

Portgroup Portgroup interface

Pos-channel POS Channel of interfaces

SYSCLOCK Telecom-Bus Clock Controller

Tunnel Tunnel interface

Vif PGM Multicast Host interface

 

Sw4#sh udld f0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

Sw4#

*Mar 6 23:00:46.072: Checking if multiple neighbors (Fa0/24)

*Mar 6 23:00:46.072: No entries in cache: no neighbors (Fa0/24)

*Mar 6 23:00:46.072: Checking if multiple neighbors (Fa0/24)

*Mar 6 23:00:46.072: No entries in cache: no neighbors (Fa0/24)

Sw4#

 

 

Interesting?

 

What was UDLD global supposed to do again?

 

Maybe I'm not waiting long enough so let's what the counter messages and pay attention to the time stamps.

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Thought I'd double-check for a sanity's sake:

 

Sw4#

*Mar 6 23:02:25.480: Checking if multiple neighbors (Fa0/24)

*Mar 6 23:02:25.480: No entries in cache: no neighbors (Fa0/24)

*Mar 6 23:02:25.480: Checking if multiple neighbors (Fa0/24)

*Mar 6 23:02:25.480: No entries in cache: no neighbors (Fa0/24)

Sw4#sh udld

 

Interface Fa0/1

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/2

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/3

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/4

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/5

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/6

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/7

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/8

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/9

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/10

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/11

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/12

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/13

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/14

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/15

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/16

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/17

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/18

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/19

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/20

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/21

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/22

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/23

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

--More--

*Mar 6 23:04:21.140: Checking if multiple neighbors (Fa0/24)

*Mar 6 23:04:21.140: No entries in cache: no neighbors (Fa0/24)

*Mar 6 23:04:21.140: Checking if multiple neighbors (Fa0/24)

*Mar 6 23:04:21.140: No entries in cache: no neighbors (Fa0/24)

*Mar 6 23:04:21.140: Checking if multiple neighbors (Fa0/24)

*Mar 6 23:04:21.140: No entries in cache: no neighbors (Fa0/24)

 

Interface Fa0/24

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Gi0/1

---

Port enable administrative configuration setting: Follows device default

Port enable operational state: Enabled

Current bidirectional state: Unknown

Current operational state: Link down

Message interval: 7

Time out interval: 5

No neighbor cache information stored

 

Interface Gi0/2

---

Port enable administrative configuration setting: Follows device default

Port enable operational state: Enabled

Current bidirectional state: Unknown

Current operational state: Link down

Message interval: 7

Time out interval: 5

No neighbor cache information stored

Sw4#

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FYI - No discrepancy - we are just not on a fiber interface on F0/24:

 

Reference:

 

http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/12.1_19_ea1/configuration/guide/swudld.html

 

 

Enabling UDLD Globally

Beginning in privileged EXEC mode, follow these steps to enable UDLD in the aggressive or normal mode and to set the configurable message timer on all fiber-optic interfaces on the switch:

 

 

Command Purpose

Step 1

configure terminal

Enter global configuration mode.

 

Step 2

udld {aggressive | enable | message time message-timer-interval}

Specify the UDLD mode of operation:

 

•aggressive—Enables UDLD in aggressive mode on all fiber-optic interfaces.

 

•enable—Enables UDLD in normal mode on all fiber-optic interfaces on the switch. UDLD is disabled by default.

 

An individual interface configuration overrides the setting of the udld enable global configuration command.

 

For more information about aggressive and normal modes, see the "Modes of Operation" section.

 

•message time message-timer-interval—Configures the period of time between UDLD probe messages on ports that are in the advertisement phase and are determined to be bidirectional. The range is from 7 to 90 seconds.

 

Note This command affects fiber-optic interfaces only. Use the udld interface configuration command to enable UDLD on other interface types. For more information, see the "Enabling UDLD on an Interface" section.

 

Step 3

end

Return to privileged EXEC mode.

 

Step 4

show udld

Verify your entries.

 

Step 5

copy running-config startup-config

(Optional) Save your entries in the configuration file.

 

 

 

To disable UDLD globally, use the no udld enable global configuration command to disable normal mode UDLD on all fiber-optic ports. Use the no udld aggressive global configuration command to disable aggressive mode UDLD on all fiber-optic ports.

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The only problem I have with the reference is that it leads us to believe that UDLD is disabled by default and according to my show udld out put and debug information, UDLD was active before I actually enabled UDLD.

 

Maybe something changed between the reference to 12.1 and my version 12.2.44?

 

 

Let's check?

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Houston I have found a discrepancy?

 

Reference:

 

http://www.cisco.com/en/US/docs/switches/lan/catalyst3550/software/release/12.2_44_se/configuration/guide/swudld.html

 

My switch's version:

 

Sw4#sh ver | i image

System image file is "flash:c3550-ipservicesk9-mz.122-44.SE.bin"

Sw4#

 

2d14h: udld_ethe

Sw3(config)#do sh ver | i image

2d14h: udld_ether_macaddr called

Sw3(config)#do sh ver | i image

System image file is "flash:c3550-ipservicesk9-mz.122-44.SE.bin"

Sw3(config)#

 

It was active and kicking "BEFORE" I enabled it.

 

Maybe my definition and Cisco's definition of disabled by default varies a little? Perhaps.

 

Default UDLD Configuration

Table 23-1 shows the default UDLD configuration.

 

 

Table 23-1 Default UDLD Configuration

Feature Default Setting

UDLD global enable state

Globally disabled

 

UDLD per-interface enable state for fiber-optic media

Disabled on all Ethernet fiber-optic interfaces

 

UDLD per-interface enable state for twisted-pair (copper) media

Disabled on all Ethernet 10/100 and 1000BASE-TX interfaces

 

UDLD aggressive mode

Disabled

Edited by Darby Weaver
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Ok - So we've established a discrepancy. Looks like UDLD is working its magic behind the scenes even when "disabled by default"?

 

Let's move on shall we.

 

Note UDLD is simply on and it is not on for non-Fiber ports while in global configuration- an important distinction.

 

Note it is NOT establishing a relationship with a neighbor while enabled globally, maybe I'll have to break out the fiber cable.

 

 

Sw3(config)#do sh udld f0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

Sw3(config)#

2d14h: Checking if multiple neighbors (Fa0/24)

2d14h: No entries in cache: no neighbors (Fa0/24)

2d14h: Checking if multiple neighbors (Fa0/24)

2d14h: No entries in cache: no neighbors (Fa0/24)

Sw3(config)#

2d14h: udld_ether_macaddr called

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I'm going to disable udld globally since it is not showing me any love.

 

Sw3(config)#no udld enable

Sw3(config)#

 

Sw4(config)#no udld en

Sw4(config)#

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Let's go ahead and go under interface f0/24 on both switches and enable UDLD locally while we are conditionally debugging.

 

Shall we?

 

Before I post this output, let me remind you this is NOT aggresssive mode... but you might want to test this on non-production boxes to see how much traffic is generated... looks like quite a bit non-stop:

 

Sw4(config-if)#udld port

Sw4(config-if)#

*Mar 6 23:22:46.108: Phase set to udld_link_up (Fa0/24)

*Mar 6 23:22:46.108: UDLD send probe message, flags = rec_timeout | resynch (Fa0/24)

*Mar 6 23:22:46.108: udld_ether_macaddr called

*Mar 6 23:22:46.108: Pr (Fa0/24)

*Mar 6 23:22:46.108: UDLD locally enabled (Fa0/24)

*Mar 6 23:22:46.648: timeout timer = 7 (Fa0/24)

*Mar 6 23:22:46.648: UDLD send probe message, flags = rec_timeout | resynch (Fa0/24)

*Mar 6 23:22:46.648: udld_ether_macaddr called

*Mar 6 23:22:46.648: Pr (Fa0/24)

Sw4(config-if)#

*Mar 6 23:22:47.648: timeout timer = 6 (Fa0/24)

*Mar 6 23:22:47.648: UDLD send probe message, flags = rec_timeout | resynch (Fa0/24)

*Mar 6 23:22:47.648: udld_ether_macaddr called

*Mar 6 23:22:47.648: Pr (Fa0/24)

*Mar 6 23:22:48.648: timeout timer = 5 (Fa0/24)

*Mar 6 23:22:48.648: UDLD send probe message, flags = rec_timeout | resynch (Fa0/24)

*Mar 6 23:22:48.648: udld_ether_macaddr called

*Mar 6 23:22:48.648: Pr (Fa0/24)

Sw4(config-if)#

*Mar 6 23:22:49.648: timeout timer = 4 (Fa0/24)

*Mar 6 23:22:49.648: UDLD send probe message, flags = rec_timeout | resynch (Fa0/24)

*Mar 6 23:22:49.648: udld_ether_macaddr called

*Mar 6 23:22:49.648: Pr (Fa0/24)

*Mar 6 23:22:50.648: timeout timer = 3 (Fa0/24)

*Mar 6 23:22:50.648: UDLD send probe message, flags = rec_timeout | resynch (Fa0/24)

*Mar 6 23:22:50.648: udld_ether_macaddr called

*Mar 6 23:22:50.648: Pr (Fa0/24)

Sw4(config-if)#

*Mar 6 23:22:51.648: timeout timer = 2 (Fa0/24)

*Mar 6 23:22:51.648: UDLD send probe message, flags = rec_timeout | resynch (Fa0/24)

*Mar 6 23:22:51.648: udld_ether_macaddr called

*Mar 6 23:22:51.648: Pr (Fa0/24)

*Mar 6 23:22:52.648: timeout timer = 1 (Fa0/24)

*Mar 6 23:22:52.648: UDLD send probe message, flags = rec_timeout | resynch (Fa0/24)

*Mar 6 23:22:52.648: udld_ether_macaddr called

*Mar 6 23:22:52.648: Pr (Fa0/24)

Sw4(config-if)#

*Mar 6 23:22:53.648: timeout timer = 0 (Fa0/24)

*Mar 6 23:22:53.648: Phase set to udld_advertisement from phase udld_link_up. (Fa0/24)

*Mar 6 23:22:53.648: Phase set to udld_advertisement after timer_expired. (Fa0/24)

*Mar 6 23:22:53.648: UDLD send probe message, flags = rec_timeout (Fa0/24)

*Mar 6 23:22:53.648: udld_ether_macaddr called

*Mar 6 23:22:53.648: P (Fa0/24)

Sw4(config-if)#

*Mar 6 23:23:00.648: UDLD send probe message, flags = rec_timeout (Fa0/24)

*Mar 6 23:23:00.648: udld_ether_macaddr called

*Mar 6 23:23:00.648: P (Fa0/24)

Sw4(config-if)#

TS4#9

[Resuming connection 9 to s3 ... ]

 

2d1

Sw3(config)#

2d15h: udld process packet received, length 84 (Fa0/24)

2d15h: Port disabled for udld (Fa0/24)

2d15h: Udld receive packet *END*. (Fa0/24)

Sw3(config)#

2d15h: udld_ether_macaddr called

Sw3(config)#int f0/24

Sw3(config-if)#ud

2d15h: udld process packet received, length 84 (Fa0/24)

2d15h: Port disabled for udld (Fa0/24)

2d15h: Udld receive packet *END*. (Fa0/24)

Sw3(config-if)#udld

2d15h: udld_ether_macaddr called

Sw3(config-if)#udld port

Sw3(config-if)#

2d15h: Phase set to udld_link_up (Fa0/24)

2d15h: UDLD send probe message, flags = rec_timeout | resynch (Fa0/24)

2d15h: udld_ether_macaddr called

2d15h: Pr (Fa0/24)

2d15h: UDLD locally enabled (Fa0/24)

2d15h: udld process packet received, length 105 (Fa0/24)

2d15h: 22 00 D2 28 00 01 00 0F 43 41 54 30 37 30 39 58 30 55 36 00

2d15h: 02 00 0A 46 61 30 2F 32 34 00 03 00 1D 00 00 00 01 00 0B 43

2d15h: 41 54 30 37 33 38 58 31 53 38 00 06 46 61 30 2F 32 34 00 04

2d15h: 00 05 07 00 05 00 05 05 00 06

Sw3(config-if)#00 07 53 77 34 00 07 00 08 00

2d15h: 00 00 01

2d15h: TLV = 1 TLV length = 15 (Fa0/24)

2d15h: item_len[1] = 12 (Fa0/24)

2d15h: Bytes left = 64 (Fa0/24)

2d15h: TLV = 2 TLV length = 10 (Fa0/24)

2d15h: item_len[2] = 7 (Fa0/24)

2d15h: Bytes left = 54 (Fa0/24)

2d15h: TLV = 3 TLV length = 29 (Fa0/24)

2d15h: Bytes left = 25 (Fa0/24)

2d15h: TLV = 4 TLV length = 5 (Fa0/24)

2d15h: item_len[4] = 1 (Fa0/24)

2d15h: Bytes left = 20 (Fa0/24)

2d15h: TLV = 5 TLV length = 5 (Fa0/24)

2d15h: item_len[5] = 1 (Fa

Sw3(config-if)#0/24)

2d15h: Bytes left = 15 (Fa0/24)

2d15h: TLV = 6 TLV length = 7 (Fa0/24)

2d15h: item_len[6] = 4 (Fa0/24)

2d15h: Bytes left = 8 (Fa0/24)

2d15h: TLV = 7 TLV length = 8 (Fa0/24)

2d15h: item_len[7] = 4 (Fa0/24)

2d15h: Bytes left = 0 (Fa0/24)

2d15h: Parse packet info and insert entry (0x28D6000) into cache. (Fa0/24)

2d15h: Cached TLV #1 = CAT0709X0U6, length = 11 (Fa0/24)

2d15h: Cached TLV #2 = Fa0/24, length = 6 (Fa0/24)

2d15h: udld_handle_bidirdetect_info (Fa0/24)

2d15h: udld_handle_bidirdetec

Sw3(config-if)#t_info pair left = 1 (Fa0/24)

2d15h: CAT0738X1S8 device (Fa0/24)

2d15h: udld_handle_bidirdetect_info: good packet (Fa0/24)

2d15h: Cached TLV #4 = 7, length = 0 (Fa0/24)

2d15h: Cached TLV #5 = 5, length = 0 (Fa0/24)

2d15h: Cached TLV #6 = Sw4, length = 3 (Fa0/24)

2d15h: Cached TLV #7, val = 3 length = 1 (Fa0/24)

2d15h: New_entry = 28D6000 (Fa0/24)

2d15h: Device Index = 1 (Fa0/24)

2d15h: First entry (Fa0/24)

2d15h: Echo packet (Fa0/24)

2d15h: Checking if multiple neighbors (Fa0/24)

2d15h: Single

Sw3(config-if)#neighbor detected (Fa0/24)

2d15h: Checking if link is bidirectional (Fa0/24)

2d15h: Found my own ID pair in 2way conn list (Fa0/24)

2d15h: Non-RSY new neighbor (Fa0/24)

2d15h: Udld entering detection phase. (Fa0/24)

2d15h: UDLD send echo message, flags = 0 (Fa0/24)

2d15h: udld_ether_macaddr called

2d15h: E (Fa0/24)

2d15h: Checking if multiple neighbors (Fa0/24)

2d15h: Single neighbor detected (Fa0/24)

2d15h: Checking if link is bidirectional (Fa0/24)

2d15h: Found my own ID pair in 2way conn lis

Sw3(config-if)#t (Fa0/24)

2d15h: Checking if multiple neighbors (Fa0/24)

2d15h: Single neighbor detected (Fa0/24)

2d15h: Checking if link is bidirectional (Fa0/24)

2d15h: Found my own ID pair in 2way conn list (Fa0/24)

2d15h: UDLD FSM updated port, bi-flag udld_bidir_detected, phase udld_detection (Fa0/24)

2d15h: Udld receive packet *END*. (Fa0/24)

2d15h: udld process packet received, length 105 (Fa0/24)

2d15h: 22 00 D2 27 00 01 00 0F 43 41 54 30 37 30 39 58 30 55 36 00

2d15h: 02 00 0A 46 61 30 2F 32 34 00 03

Sw3(config-if)#00 1D 00 00 00 01 00 0B 43

2d15h: 41 54 30 37 33 38 58 31 53 38 00 06 46 61 30 2F 32 34 00 04

2d15h: 00 05 07 00 05 00 05 05 00 06 00 07 53 77 34 00 07 00 08 00

2d15h: 00 00 02

2d15h: TLV = 1 TLV length = 15 (Fa0/24)

2d15h: item_len[1] = 12 (Fa0/24)

2d15h: Bytes left = 64 (Fa0/24)

2d15h: TLV = 2 TLV length = 10 (Fa0/24)

2d15h: item_len[2] = 7 (Fa0/24)

2d15h: Bytes left = 54 (Fa0/24)

2d15h: TLV = 3 TLV length = 29 (Fa0/24)

2d15h: Bytes left = 25 (Fa0/24)

2d15h: TLV = 4 TLV length = 5 (Fa0/24

Sw3(config-if)#)

2d15h: item_len[4] = 1 (Fa0/24)

2d15h: Bytes left = 20 (Fa0/24)

2d15h: TLV = 5 TLV length = 5 (Fa0/24)

2d15h: item_len[5] = 1 (Fa0/24)

2d15h: Bytes left = 15 (Fa0/24)

2d15h: TLV = 6 TLV length = 7 (Fa0/24)

2d15h: item_len[6] = 4 (Fa0/24)

2d15h: Bytes left = 8 (Fa0/24)

2d15h: TLV = 7 TLV length = 8 (Fa0/24)

2d15h: item_len[7] = 4 (Fa0/24)

2d15h: Bytes left = 0 (Fa0/24)

2d15h: Parse packet info and insert entry (0x2C581E4) into cache. (Fa0/24)

2d15h: Cached TLV #1 = CAT0709X0U6, length = 11 (F

Sw3(config-if)#a0/24)

2d15h: Cached TLV #2 = Fa0/24, length = 6 (Fa0/24)

2d15h: udld_handle_bidirdetect_info (Fa0/24)

2d15h: udld_handle_bidirdetect_info pair left = 1 (Fa0/24)

2d15h: CAT0738X1S8 device (Fa0/24)

2d15h: udld_handle_bidirdetect_info: good packet (Fa0/24)

2d15h: Cached TLV #4 = 7, length = 0 (Fa0/24)

2d15h: Cached TLV #5 = 5, length = 0 (Fa0/24)

2d15h: Cached TLV #6 = Sw4, length = 3 (Fa0/24)

2d15h: Cached TLV #7, val = 3 length = 2 (Fa0/24)

2d15h: New_entry = 2C581E4 (Fa0/24)

2d15h: Found an ent

Sw3(config-if)#ry from same device (Fa0/24)

2d15h: Cached entries = 2 (Fa0/24)

2d15h: Entry (0x28D6000) deleted: 1 entries cached

2d15h: Cached entries = 1 (Fa0/24)

2d15h: Echo packet (Fa0/24)

2d15h: Checking if multiple neighbors (Fa0/24)

2d15h: Single neighbor detected (Fa0/24)

2d15h: Checking if link is bidirectional (Fa0/24)

2d15h: Found my own ID pair in 2way conn list (Fa0/24)

2d15h: Checking if multiple neighbors (Fa0/24)

2d15h: Single neighbor detected (Fa0/24)

2d15h: Checking if link is bidirectional

Sw3(config-if)#(Fa0/24)

2d15h: Found my own ID pair in 2way conn list (Fa0/24)

2d15h: UDLD FSM updated port, bi-flag udld_bidir_detected, phase udld_detection (Fa0/24)

2d15h: Udld receive packet *END*. (Fa0/24)

2d15h: timeout timer = 4 (Fa0/24)

2d15h: UDLD send echo message, flags = 0 (Fa0/24)

2d15h: udld_ether_macaddr called

2d15h: E (Fa0/24)

2d15h: udld process packet received, length 105 (Fa0/24)

2d15h: 22 00 D2 26 00 01 00 0F 43 41 54 30 37 30 39 58 30 55 36 00

2d15h: 02 00 0A 46 61 30 2F 32 34 00 03 00 1

Sw3(config-if)#D 00 00 00 01 00 0B 43

2d15h: 41 54 30 37 33 38 58 31 53 38 00 06 46 61 30 2F 32 34 00 04

2d15h: 00 05 07 00 05 00 05 05 00 06 00 07 53 77 34 00 07 00 08 00

2d15h: 00 00 03

2d15h: TLV = 1 TLV length = 15 (Fa0/24)

2d15h: item_len[1] = 12 (Fa0/24)

2d15h: Bytes left = 64 (Fa0/24)

2d15h: TLV = 2 TLV length = 10 (Fa0/24)

2d15h: item_len[2] = 7 (Fa0/24)

2d15h: Bytes left = 54 (Fa0/24)

2d15h: TLV = 3 TLV length = 29 (Fa0/24)

2d15h: Bytes left = 25 (Fa0/24)

2d15h: TLV = 4 TLV length = 5 (Fa0/24)

2

Sw3(config-if)#d15h: item_len[4] = 1 (Fa0/24)

2d15h: Bytes left = 20 (Fa0/24)

2d15h: TLV = 5 TLV length = 5 (Fa0/24)

2d15h: item_len[5] = 1 (Fa0/24)

2d15h: Bytes left = 15 (Fa0/24)

2d15h: TLV = 6 TLV length = 7 (Fa0/24)

2d15h: item_len[6] = 4 (Fa0/24)

2d15h: Bytes left = 8 (Fa0/24)

2d15h: TLV = 7 TLV length = 8 (Fa0/24)

2d15h: item_len[7] = 4 (Fa0/24)

2d15h: Bytes left = 0 (Fa0/24)

2d15h: Parse packet info and insert entry (0x28D6000) into cache. (Fa0/24)

2d15h: Cached TLV #1 = CAT0709X0U6, length = 11 (Fa0/2

Sw3(config-if)#4)

2d15h: Cached TLV #2 = Fa0/24, length = 6 (Fa0/24)

2d15h: udld_handle_bidirdetect_info (Fa0/24)

2d15h: udld_handle_bidirdetect_info pair left = 1 (Fa0/24)

2d15h: CAT0738X1S8 device (Fa0/24)

2d15h: udld_handle_bidirdetect_info: good packet (Fa0/24)

2d15h: Cached TLV #4 = 7, length = 0 (Fa0/24)

2d15h: Cached TLV #5 = 5, length = 0 (Fa0/24)

2d15h: Cached TLV #6 = Sw4, length = 3 (Fa0/24)

2d15h: Cached TLV #7, val = 3 length = 3 (Fa0/24)

2d15h: New_entry = 28D6000 (Fa0/24)

2d15h: Found an entry f

Sw3(config-if)#rom same device (Fa0/24)

2d15h: Cached entries = 2 (Fa0/24)

2d15h: Entry (0x2C581E4) deleted: 1 entries cached

2d15h: Cached entries = 1 (Fa0/24)

2d15h: Echo packet (Fa0/24)

2d15h: Checking if multiple neighbors (Fa0/24)

2d15h: Single neighbor detected (Fa0/24)

2d15h: Checking if link is bidirectional (Fa0/24)

2d15h: Found my own ID pair in 2way conn list (Fa0/24)

2d15h: Checking if multiple neighbors (Fa0/24)

2d15h: Single neighbor detected (Fa0/24)

2d15h: Checking if link is bidirectional (Fa0

Sw3(config-if)#/24)

2d15h: Found my own ID pair in 2way conn list (Fa0/24)

2d15h: UDLD FSM updated port, bi-flag udld_bidir_detected, phase udld_detection (Fa0/24)

2d15h: Udld receive packet *END*. (Fa0/24)

2d15h: timeout timer = 3 (Fa0/24)

2d15h: UDLD send echo message, flags = 0 (Fa0/24)

2d15h: udld_ether_macaddr called

2d15h: E (Fa0/24)

2d15h: udld process packet received, length 105 (Fa0/24)

2d15h: 22 00 D2 25 00 01 00 0F 43 41 54 30 37 30 39 58 30 55 36 00

2d15h: 02 00 0A 46 61 30 2F 32 34 00 03 00 1D 00

Sw3(config-if)# 00 00 01 00 0B 43

2d15h: 41 54 30 37 33 38 58 31 53 38 00 06 46 61 30 2F 32 34 00 04

2d15h: 00 05 07 00 05 00 05 05 00 06 00 07 53 77 34 00 07 00 08 00

2d15h: 00 00 04

2d15h: TLV = 1 TLV length = 15 (Fa0/24)

2d15h: item_len[1] = 12 (Fa0/24)

2d15h: Bytes left = 64 (Fa0/24)

2d15h: TLV = 2 TLV length = 10 (Fa0/24)

2d15h: item_len[2] = 7 (Fa0/24)

2d15h: Bytes left = 54 (Fa0/24)

2d15h: TLV = 3 TLV length = 29 (Fa0/24)

2d15h: Bytes left = 25 (Fa0/24)

2d15h: TLV = 4 TLV length = 5 (Fa0/24)

2d15h

Sw3(config-if)#: item_len[4] = 1 (Fa0/24)

2d15h: Bytes left = 20 (Fa0/24)

2d15h: TLV = 5 TLV length = 5 (Fa0/24)

2d15h: item_len[5] = 1 (Fa0/24)

2d15h: Bytes left = 15 (Fa0/24)

2d15h: TLV = 6 TLV length = 7 (Fa0/24)

2d15h: item_len[6] = 4 (Fa0/24)

2d15h: Bytes left = 8 (Fa0/24)

2d15h: TLV = 7 TLV length = 8 (Fa0/24)

2d15h: item_len[7] = 4 (Fa0/24)

2d15h: Bytes left = 0 (Fa0/24)

2d15h: Parse packet info and insert entry (0x2C581E4) into cache. (Fa0/24)

2d15h: Cached TLV #1 = CAT0709X0U6, length = 11 (Fa0/24)

 

Sw3(config-if)#2d15h: Cached TLV #2 = Fa0/24, length = 6 (Fa0/24)

2d15h: udld_handle_bidirdetect_info (Fa0/24)

2d15h: udld_handle_bidirdetect_info pair left = 1 (Fa0/24)

2d15h: CAT0738X1S8 device (Fa0/24)

2d15h: udld_handle_bidirdetect_info: good packet (Fa0/24)

2d15h: Cached TLV #4 = 7, length = 0 (Fa0/24)

2d15h: Cached TLV #5 = 5, length = 0 (Fa0/24)

2d15h: Cached TLV #6 = Sw4, length = 3 (Fa0/24)

2d15h: Cached TLV #7, val = 3 length = 4 (Fa0/24)

2d15h: New_entry = 2C581E4 (Fa0/24)

2d15h: Found an entry from

Sw3(config-if)#same device (Fa0/24)

2d15h: Cached entries = 2 (Fa0/24)

2d15h: Entry (0x28D6000) deleted: 1 entries cached

2d15h: Cached entries = 1 (Fa0/24)

2d15h: Echo packet (Fa0/24)

2d15h: Checking if multiple neighbors (Fa0/24)

2d15h: Single neighbor detected (Fa0/24)

2d15h: Checking if link is bidirectional (Fa0/24)

2d15h: Found my own ID pair in 2way conn list (Fa0/24)

2d15h: Checking if multiple neighbors (Fa0/24)

2d15h: Single neighbor detected (Fa0/24)

2d15h: Checking if link is bidirectional (Fa0/24)

Sw3(config-if)#

2d15h: Found my own ID pair in 2way conn list (Fa0/24)

2d15h: UDLD FSM updated port, bi-flag udld_bidir_detected, phase udld_detection (Fa0/24)

2d15h: Udld receive packet *END*. (Fa0/24)

2d15h: timeout timer = 2 (Fa0/24)

2d15h: UDLD send echo message, flags = 0 (Fa0/24)

2d15h: udld_ether_macaddr called

2d15h: E (Fa0/24)

2d15h: udld process packet received, length 105 (Fa0/24)

2d15h: 22 00 D2 24 00 01 00 0F 43 41 54 30 37 30 39 58 30 55 36 00

2d15h: 02 00 0A 46 61 30 2F 32 34 00 03 00 1D 00 00

Sw3(config-if)#00 01 00 0B 43

2d15h: 41 54 30 37 33 38 58 31 53 38 00 06 46 61 30 2F 32 34 00 04

2d15h: 00 05 07 00 05 00 05 05 00 06 00 07 53 77 34 00 07 00 08 00

2d15h: 00 00 05

2d15h: TLV = 1 TLV length = 15 (Fa0/24)

2d15h: item_len[1] = 12 (Fa0/24)

2d15h: Bytes left = 64 (Fa0/24)

2d15h: TLV = 2 TLV length = 10 (F

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I'm going to undebug one side so I can run my show commands and have time to catch them...

 

This UDLD is ultra chatty even for just a single port.

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There we go - Undebugged:

 

Sw4(config-if)#do u al

*Mar 6 23:26:35.648: UDLD send probe message, flags = rec_timeout (Fa0/24)

*Mar 6 23:26:35.648: udld_ether_macaddr called

*Mar 6 23:26:35.648: P (Fa0/24)

*Mar 6 23:26:35.664: udld process packet received, length 105 (Fa0/24)

*Mar 6 23:26:35.664: 21 01 CB 19 00 01 00 0F 43 41 54 30 37 33 38 58 31 53 38 00

*Mar 6 23:26:35.664: 02 00 0A 46 61 30 2F 32 34 00 03 00 1D 00 00 00 01 00 0B 43

*Mar 6 23:26:35.664: 41 54 30 37 30 39 58 30 55 36 00 06 46 61 30 2F 32 34 00 04

*Mar 6 23:26:35.664: 00

Sw4(config-if)#do u all

All possible debugging has been turned off

Sw4(config-if)# 05 0F 00 05 00 05 05 00 06 00 07 53 77 33 00 07 00 08 00

*Mar 6 23:26:35.664: 00 00 10

*Mar 6 23:26:35.664: TLV = 1 TLV length = 15 (Fa0/24)

*Mar 6 23:26:35.664: item_len[1] = 12 (Fa0/24)

*Mar 6 23:26:35.664: Bytes left = 64 (Fa0/24)

*Mar 6 23:26:35.664: TLV = 2 TLV length = 10 (Fa0/24)

*Mar 6 23:26:35.664: item_len[2] = 7 (Fa0/24)

*Mar 6 23:26:35.664: Bytes left = 54 (Fa0/24)

*Mar 6 23:26:35.664: TLV = 3 TLV length = 29 (Fa0/24)

*Mar 6 23:26:35.664: Bytes

Sw4(config-if)#left = 25 (Fa0/24)

*Mar 6 23:26:35.664: TLV = 4 TLV length = 5 (Fa0/24)

*Mar 6 23:26:35.664: item_len[4] = 1 (Fa0/24)

*Mar 6 23:26:35.664: Bytes left = 20 (Fa0/24)

*Mar 6 23:26:35.664: TLV = 5 TLV length = 5 (Fa0/24)

*Mar 6 23:26:35.664: item_len[5] = 1 (Fa0/24)

*Mar 6 23:26:35.664: Bytes left = 15 (Fa0/24)

*Mar 6 23:26:35.664: TLV = 6 TLV length = 7 (Fa0/24)

*Mar 6 23:26:35.664: item_len[6] = 4 (Fa0/24)

*Mar 6 23:26:35.664: Bytes left = 8 (Fa0/24)

*Mar 6 23:26:35.664: TLV = 7 TLV lengt

Sw4(config-if)#h = 8 (Fa0/24)

*Mar 6 23:26:35.664: item_len[7] = 4 (Fa0/24)

*Mar 6 23:26:35.664: Bytes left = 0 (Fa0/24)

*Mar 6 23:26:35.668: Parse packet info and insert entry (0x2CA6D38) into cache. (Fa0/24)

*Mar 6 23:26:35.668: Cached TLV #1 = CAT0738X1S8, length = 11 (Fa0/24)

*Mar 6 23:26:35.668: Cached TLV #2 = Fa0/24, length = 6 (Fa0/24)

*Mar 6 23:26:35.668: udld_handle_bidirdetect_info (Fa0/24)

*Mar 6 23:26:35.668: udld_handle_bidirdetect_info pair left = 1 (Fa0/24)

*Mar 6 23:26:35.668: CAT0709X0U6

Sw4(config-if)# device (Fa0/24)

*Mar 6 23:26:35.668: udld_handle_bidirdetect_info: good packet (Fa0/24)

*Mar 6 23:26:35.668: Cached TLV #4 = 15, length = 0 (Fa0/24)

*Mar 6 23:26:35.668: Cached TLV #5 = 5, length = 0 (Fa0/24)

*Mar 6 23:26:35.668: Cached TLV #6 = Sw3, length = 3 (Fa0/24)

*Mar 6 23:26:35.668: Cached TLV #7, val = 3 length = 16 (Fa0/24)

*Mar 6 23:26:35.668: New_entry = 2CA6D38 (Fa0/24)

*Mar 6 23:26:35.668: Found an entry from same device (Fa0/24)

*Mar 6 23:26:35.668: Cached entries = 2 (Fa0/2

Sw4(config-if)#4)

*Mar 6 23:26:35.668: Entry (0x2CA6DF4) deleted: 1 entries cached

*Mar 6 23:26:35.668: Cached entries = 1 (Fa0/24)

*Mar 6 23:26:35.668: Probe packet (Fa0/24)

*Mar 6 23:26:35.668: Checking if multiple neighbors (Fa0/24)

*Mar 6 23:26:35.668: Single neighbor detected (Fa0/24)

*Mar 6 23:26:35.668: Checking if link is bidirectional (Fa0/24)

*Mar 6 23:26:35.668: Found my own ID pair in 2way conn list (Fa0/24)

*Mar 6 23:26:35.668: Udld receive packet *END*. (Fa0/24)

Sw4(config-if)#

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Anyone starting to see why I don't believe in "3-Month CCIE Braniacs"?

 

Look how long it is taking to test a very simple protocol - just one.

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Here's a show udld at the moment and remember just one port.

 

Cisco "recommended" 15 seconds but it is that way by default for the message timer. It's talking more often than that by far if the debugs are not lying.

 

 

Sw4#sh udld

 

Interface Fa0/1

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/2

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/3

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/4

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/5

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/6

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/7

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/8

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/9

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/10

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/11

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/12

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/13

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/14

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/15

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/16

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/17

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/18

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/19

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/20

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/21

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/22

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/23

---

Port enable administrative configuration setting: Disabled

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Fa0/24

---

Port enable administrative configuration setting: Enabled

Port enable operational state: Enabled

Current bidirectional state: Bidirectional

Current operational state: Advertisement - Single neighbor detected

Message interval: 15

Time out interval: 5

 

Interface Gi0/1

---

Port enable administrative configuration setting: Follows device default

Port enable operational state: Disabled

Current bidirectional state: Unknown

 

Interface Gi0/2

---

Port enable administrative configuration setting: Follows device default

Port enable operational state: Disabled

Current bidirectional state: Unknown

Sw4#

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Sw4#sh clock

*23:38:21.880 UTC Sat Mar 6 1993

Sw4#do s

*Mar 6 23:38:29.684: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/24, changed state to down

Sw4#do s

*Mar 6 23:38:30.688: %LINK-3-UPDOWN: Interface FastEthernet0/24, changed state to down

Sw4#sh udld f0/24 ?

| Output modifiers

<cr>

 

Sw4#sh udld f0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Enabled

Port enable operational state: Enabled

Current bidirectional state: Unknown

Current operational state: Link down

Message interval: 15

Time out interval: 5

No neighbor cache information stored

Sw4#sh int f0/24

FastEthernet0/24 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 000c.30d2.1798 (bia 000c.30d2.1798)

MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation ARPA, loopback not set

Keepalive set (10 sec)

Auto-duplex, Auto-speed, media type is 10/100BaseTX

input flow-control is off, output flow-control is unsupported

ARP type: ARPA, ARP Timeout 04:00:00

Last input 00:00:44, output 00:00:36, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

5 minute input rate 0 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec

401307 packets input, 33004053 bytes, 0 no buffer

Received 372053 broadcasts (0 multicasts)

0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored

0 watchdog, 372022 multicast, 0 pause input

0 input packets with dribble condition detected

517471 packets output, 40528220 bytes, 0 underruns

Edited by Darby Weaver
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*Mar 6 23:26:35.668: udld_handle_bidirdetect_info: good packet (Fa0/24)

*Mar 6 23:26:35.668: Cached TLV #4 = 15, length = 0 (Fa0/24)

*Mar 6 23:26:35.668: Cached TLV #5 = 5, length = 0 (Fa0/24)

*Mar 6 23:26:35.668: Cached TLV #6 = Sw3, length = 3 (Fa0/24)

*Mar 6 23:26:35.668: Cached TLV #7, val = 3 length = 16 (Fa0/24)

*Mar 6 23:26:35.668: New_entry = 2CA6D38 (Fa0/24)

*Mar 6 23:26:35.668: Found an entry from same device (Fa0/24)

*Mar 6 23:26:35.668: Cached entries = 2 (Fa0/24)

*Mar 6 23:26:35.668: Entry (0x2CA6DF4) deleted: 1 entries cached

*Mar 6 23:26:35.668: Cached entries = 1 (Fa0/24)

*Mar 6 23:26:35.668: Probe packet (Fa0/24)

*Mar 6 23:26:35.668: Checking if multiple neighbors (Fa0/24)

*Mar 6 23:26:35.668: Single neighbor detected (Fa0/24)

*Mar 6 23:26:35.668: Checking if link is bidirectional (Fa0/24)

*Mar 6 23:26:35.668: Found my own ID pair in 2way conn list (Fa0/24)

*Mar 6 23:26:35.668: Udld receive packet *END*. (Fa0/24)

*Mar 6 23:28:46.484: %SYS-5-CONFIG_I: Configured from console by console

*Mar 6 23:38:29.684: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/24, changed state to down

*Mar 6 23:38:30.688: %LINK-3-UPDOWN: Interface FastEthernet0/24, changed state to down

 

 

 

 

This is from the link where the cable was not removed.

 

Sw4# sh int f0/24 | i Fast

FastEthernet0/24 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 000c.30d2.1798 (bia 000c.30d2.1798)

Sw4#

 

This from the switch where the cable is dangling.

 

Sw3(config-if)#do sh int f0/24 | i Fast

FastEthernet0/24 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 000d.ed2f.e598 (bia 000d.ed2f.e598)

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Let's get aggressive...

 

And see if we can force an err-disable...

 

Kinda lame so far...

 

Looks like I lied to you since this is just not happening:

 

 

 

UDLD is designed to mitigate fault conditions on both Ethernet and Fiber interfaces. It does this shutting down the interfaces that may be either miswired or where a fault has occurred and then putting those ports in Err-Disable Mode.

 

 

Shutdown: yes

 

Err-Disable: no

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Maybe we need an actual wiring fault?

 

Not just a disconnected cable?

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Sw4(config-if)#udld port aggressive

Sw4(config-if)#do sh run int f0/24

Building configuration...

 

Current configuration : 197 bytes

!

interface FastEthernet0/24

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 2,3,11,13,15,22,24,44,45

switchport mode trunk

switchport nonegotiate

udld port aggressive

end

 

Sw4(config-if)#

 

 

Sw4(config-if)#do sh udld f0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Enabled / in aggressive mode

Port enable operational state: Enabled / in aggressive mode

Current bidirectional state: Bidirectional

Current operational state: Advertisement - Single neighbor detected

Message interval: 15

Time out interval: 5

 

Entry 1

---

Expiration time: 44

Cache Device index: 1

Current neighbor state: Bidirectional

Device ID: CAT0738X1S8

Port ID: Fa0/24

Neighbor echo 1 device: CAT0709X0U6

Neighbor echo 1 port: Fa0/24

 

Message interval: 15

Time out interval: 5

CDP Device name: Sw3

Sw4(config-if)#

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Note: I only configured one side for aggressive so far:

 

 

 

 

Sw4(config-if)#do sh udld f0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Enabled / in aggressive mode

Port enable operational state: Enabled / in aggressive mode

Current bidirectional state: Bidirectional

Current operational state: Advertisement - Single neighbor detected

Message interval: 15

Time out interval: 5

 

Entry 1

---

Expiration time: 44

Cache Device index: 1

Current neighbor state: Bidirectional

Device ID: CAT0738X1S8

Port ID: Fa0/24

Neighbor echo 1 device: CAT0709X0U6

Neighbor echo 1 port: Fa0/24

 

Message interval: 15

Time out interval: 5

CDP Device name: Sw3

Sw4(config-if)#

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So I notice UDLD references a CDP value... so I turn off CDP to see if the puppy will scream or... not:

 

Sw3(config-if)#do sh cdp nei f0/24

Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge

S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

 

Device ID Local Intrfce Holdtme Capability Platform Port ID

Sw4 Fas 0/24 1 R S I WS-C3550- Fas 0/24

Sw3(config-if)#do sh cdp nei f0/24

Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge

S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

 

Device ID Local Intrfce Holdtme Capability Platform Port ID

Sw3(config-if)#do sh udld f0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Enabled

Port enable operational state: Enabled

Current bidirectional state: Bidirectional

Current operational state: Advertisement - Single neighbor detected

Message interval: 15

Time out interval: 5

 

Entry 1

---

Expiration time: 34

Cache Device index: 1

Current neighbor state: Bidirectional

Device ID: CAT0709X0U6

Port ID: Fa0/24

Neighbor echo 1 device: CAT0738X1S8

Neighbor echo 1 port: Fa0/24

 

Message interval: 15

Time out interval: 5

CDP Device name: Sw4

Sw3(config-if)#do sh udld f0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Enabled

Port enable operational state: Enabled

Current bidirectional state: Bidirectional

Current operational state: Advertisement - Single neighbor detected

Message interval: 15

Time out interval: 5

 

Entry 1

---

Expiration time: 38

Cache Device index: 1

Current neighbor state: Bidirectional

Device ID: CAT0709X0U6

Port ID: Fa0/24

Neighbor echo 1 device: CAT0738X1S8

Neighbor echo 1 port: Fa0/24

 

Message interval: 15

Time out interval: 5

CDP Device name: Sw4

Sw3(config-if)#

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Sw3(config-if)# do sh cloc

*15:38:48.476 UTC Wed Mar 3 1993

Sw3(config-if)#do sh udld f0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Enabled

Port enable operational state: Enabled

Current bidirectional state: Bidirectional

Current operational state: Advertisement - Single neighbor detected

Message interval: 15

Time out interval: 5

 

Entry 1

---

Expiration time: 45

Cache Device index: 1

Current neighbor state: Bidirectional

Device ID: CAT0709X0U6

Port ID: Fa0/24

Neighbor echo 1 device: CAT0738X1S8

Neighbor echo 1 port: Fa0/24

 

Message interval: 15

Time out interval: 5

CDP Device name: Sw4

Sw3(config-if)# do sh cloc

*15:42:21.256 UTC Wed Mar 3 1993

Sw3(config-if)#

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Unplugged...

 

Err-Disable?

 

Sw3(config-if)#

2d15h: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/24, changed state to down

Sw3(config-if)#

2d15h: %LINK-3-UPDOWN: Interface FastEthernet0/24, changed state to down

Sw3(config-if)#do sh udld f0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Enabled

Port enable operational state: Enabled

Current bidirectional state: Unknown

Current operational state: Link down

Message interval: 15

Time out interval: 5

No neighbor cache information stored

Sw3(config-if)#do sh int f0/24 | i Fast

FastEthernet0/24 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 000d.ed2f.e598 (bia 000d.ed2f.e598)

Sw3(config-if)#

 

Sw4(config-if)#do sh int f0/24 | i Fast

FastEthernet0/24 is down, line protocol is down (notconnect)

Hardware is Fast Ethernet, address is 000c.30d2.1798 (bia 000c.30d2.1798)

Sw4(config-if)#

 

 

I guess disconnected interfaces don't get Err-Disable love?

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Sw4(config-if)#do sh run int f0/24

Building configuration...

 

Current configuration : 212 bytes

!

interface FastEthernet0/24

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 2,3,11,13,15,22,24,44,45

switchport mode trunk

switchport nonegotiate

udld port aggressive

no cdp enable

end

 

Sw4(config-if)#

TS4#9

[Resuming connection 9 to s3 ... ]

 

Sw3(config-if)#do sh run int f0/24

Building configuration...

 

Current configuration : 186 bytes

!

interface FastEthernet0/24

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 2,3,11,13,15,22,24,44,45

switchport mode trunk

switchport nonegotiate

udld port

end

 

Sw3(config-if)#int f0/24

Sw3(config-if)#udld port agg

Sw3(config-if)#d

2d15h: %LINK-3-UPDOWN: Interface FastEthernet0/24, changed state to up

2d15h: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/24, changed state to up

Sw3(config-if)#exit

Sw3(config)#do sh err

Sw3(config)#do sh err

sh err

% Incomplete command.

 

Sw3(config)#exit

Sw3#sh

2d15h: %SYS-5-CONFIG_I: Configured from console by console

Sw3#sh err ?

detect Error disable detection

flap-values Flap values for error disable detection

recovery Error disable recovery

 

Sw3#sh err detect ?

| Output modifiers

<cr>

 

Sw3#sh err detect

ErrDisable Reason Detection Mode

----------------- --------- ----

arp-inspection Enabled port

bpduguard Enabled port

channel-misconfig Enabled port

community-limit Enabled port

dhcp-rate-limit Enabled port

dtp-flap Enabled port

ekey Enabled port

gbic-invalid Enabled port

inline-power Enabled port

invalid-policy Enabled port

l2ptguard Enabled port

link-flap Enabled port

link-monitor-failur Enabled port

loopback Enabled port

lsgroup Enabled port

oam-remote-failure Enabled port

mac-limit Enabled port

pagp-flap Enabled port

port-mode-failure Enabled port

psecure-violation Enabled port/vlan

security-violation Enabled port

sfp-config-mismatch Enabled port

storm-control Enabled port

udld Enabled port

unicast-flood Enabled port

vmps Enabled port

Sw3#sh err rec

ErrDisable Reason Timer Status

----------------- --------------

arp-inspection Disabled

bpduguard Disabled

channel-misconfig Disabled

dhcp-rate-limit Disabled

dtp-flap Disabled

gbic-invalid Disabled

inline-power Disabled

l2ptguard Disabled

link-flap Disabled

mac-limit Disabled

link-monitor-fail Disabled

loopback Disabled

oam-remote-failur Disabled

pagp-flap Disabled

port-mode-failure Disabled

psecure-violation Disabled

security-violatio Disabled

sfp-config-mismat Disabled

storm-control Disabled

udld Disabled

unicast-flood Disabled

vmps Disabled

 

Timer interval: 300 seconds

 

Interfaces that will be enabled at the next timeout:

 

Sw3#

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Sw3#sh run int f0/24

Building configuration...

 

Current configuration : 197 bytes

!

interface FastEthernet0/24

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 2,3,11,13,15,22,24,44,45

switchport mode trunk

switchport nonegotiate

udld port aggressive

end

 

 

 

Sw3#sh udld f0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Enabled / in aggressive mode

Port enable operational state: Enabled / in aggressive mode

Current bidirectional state: Bidirectional

Current operational state: Advertisement - Single neighbor detected

Message interval: 15

Time out interval: 5

 

Entry 1

---

Expiration time: 41

Cache Device index: 1

Current neighbor state: Bidirectional

Device ID: CAT0709X0U6

Port ID: Fa0/24

Neighbor echo 1 device: CAT0738X1S8

Neighbor echo 1 port: Fa0/24

 

Message interval: 15

Time out interval: 5

CDP Device name: Sw4

Sw3#sh cdp nei f0/24

Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge

S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone

 

Device ID Local Intrfce Holdtme Capability Platform Port ID

Sw3#

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Sw3(config-if)#

TS4#10

[Resuming connection 10 to s4 ... ]

 

*Ma

Sw4(config-if)#do sh run int f0/24

Building configuration...

 

Current configuration : 212 bytes

!

interface FastEthernet0/24

switchport trunk encapsulation dot1q

switchport trunk allowed vlan 2,3,11,13,15,22,24,44,45

switchport mode trunk

switchport nonegotiate

udld port aggressive

no cdp enable

end

 

Sw4(config-if)#cdp en

Sw4(config-if)#do sh udld f0/24

 

Interface Fa0/24

---

Port enable administrative configuration setting: Enabled / in aggressive mode

Port enable operational state: Enabled / in aggressive mode

Current bidirectional state: Bidirectional

Current operational state: Advertisement - Single neighbor detected

Message interval: 15

Time out interval: 5

 

Entry 1

---

Expiration time: 35

Cache Device index: 1

Current neighbor state: Bidirectional

Device ID: CAT0738X1S8

Port ID: Fa0/24

Neighbor echo 1 device: CAT0709X0U6

Neighbor echo 1 port: Fa0/24

 

Message interval: 15

Time out interval: 5

CDP Device name: Sw3

Sw4(config-if)#

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