UDLD scenario

This scenario describes how to use UDLD on a single physical interface as well as a LAG.

Procedure
  1. On switch A:

    1. Configure the UDLD session between switch A and B. 

      switch# config
switch(config-if)# interface 1/1/1
switch(config-if)# udld
switch(config-if)# exit
switch(config)#

    2. Configure the UDLD session between switch A and C. 

      switch(config)# interface 1/1/2
switch(config-if)# no shutdown
switch(config-if)# no routing
switch(config-if)# lag 1
switch(config-if)# udld interval 400
switch(config-if)# udld mode aruba-os verify-then-forward
switch(config-if)# udld retries 5
switch(config)# exit
switch(config)# interface 1/1/3
switch(config-if)# no shutdown
switch(config-if)# no routing
switch(config-if)# lag 1
switch(config-if)# udld interval 400
switch(config-if)# udld mode aruba-os verify-then-forward
switch(config-if)# udld retries 5
  2. On switch B, configure the UDLD session between switch B and A. 
    switch# config
switch(config-if)# interface 1/1/1
switch(config-if)# udld
switch(config-if)# exit
switch(config)#
  3. On switch C, configure the UDLD session between switch C and A. 
    switch# config
switch(config)# interface 1/1/2
switch(config-if)# no shutdown
switch(config-if)# no routing
switch(config-if)# lag 1
switch(config-if)# udld interval 400
switch(config-if)# udld mode aruba-os verify-then-forward
switch(config-if)# udld retries 5
switch(config)# exit
switch(config)# interface 1/1/3
switch(config-if)# no shutdown
switch(config-if)# no routing
switch(config-if)# lag 1
switch(config-if)# udld interval 400
switch(config-if)# udld mode aruba-os verify-then-forward
switch(config-if)# udld retries 5
  4. On switch A, verify UDLD configuration by running the command show udld. (A packet must arrive on each switch for it to unblock the interface.) 
    switch# show udld
Abbreviations:
 VTF - Verify then forward    FTV - Forward then verify
 NOR - RFC 5171 normal        AGG - RFC 5171 aggressive

---------------------------------------------------------------------------------------------------------------------------
Interface  UDLD      UDLD    UDLD           UDLD     Mode Interval Retries  Tx    Rx    Rx          Rx         Transitions
           Config    State   Substate       Link                            Pkts  Pkts  Pkts disc.  Pkts drop.
---------------------------------------------------------------------------------------------------------------------------
1/1/1      enabled   active  Bidirectional  unblock  FTV  7000     4        0     0     0           0          0
1/1/2      enabled   active  Bidirectional  unblock  VTF  400      5        2     2     0           0          1
1/1/3      enabled   active  Bidirectional  unblock  VTF  400      5        2     2     0           0          1