Cisco CDP and ATM interface

Posted on 2006-05-31
Last Modified: 2013-12-03
Some Cisco routers are connected via an ATM cloud with E3 or STM-1
WAN interface. With CDP active (default setup) no router show any
output when "sh cdp neighbors" is issued (on the ATM interface).
In the LAN interface the CDP works fine. This is a config. sample.
My question is: why the "sh cdp nei" doesn't show any neighborship
between ATM interfaces ?

Interface ATM0/0/0.1 point-to-point
 mtu 1500
 bandwidth 512
 ip address xx.xx.xx.xx
 no ip redirects
 no ip proxy-arp
 clns router isis area_bb
 pvc PVCNAME 21/101
  vbr-nrt 583 583 1376
  oam-pvc manage
  oam retry 3 5 1
  encapsulation aal5snap

Best Regards
Question by:lrinetti
    1 Comment
    LVL 10

    Accepted Solution

    cdp is not enabled by default on atm interfaces, you will need to enable it by entering the following under atm interface

    cdp enable

    once enabled on both ends, you will be able see the neighbours as it is supported on point to point AAL5SNAP subinterfaces.

    You can verify if it is sending and receiving packets by

    show cdp interface atm0/0/0.1


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