2610 Subinterface issue. Able to see cdp neighbours, but unable to ping them

[Dmitriy Rybkin]

I have a problem with my 2610 router. I have 2950 switch connected to the 2610 router using trunk connection. On the 2610 router when i assigned IP addres 192.168.0.1 to the interface e0/0 i am able to ping 192.168.0.2 -  my Vlan1 interface on the Switch. Then i deleted ip address from e0/0 interface on the router and assigned it to the subinterface e0/0.1 and immediatly i am unable to ping the e0/0.1. subinterface... but here is what i can see throuth the cdp neighbours command:

DR_Switch(config)#do show cdp neigh
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
DR_Router.dr.com
                 Fas 0/2            136           R       2610      Eth 0/0.1

DR_Switch#show cdp entry *
-------------------------
Device ID: DR_Router.dr.com
Entry address(es):
  IP address: 192.168.0.1
Platform: cisco 2610,  Capabilities: Router
Interface: FastEthernet0/2,  Port ID (outgoing port): Ethernet0/0.1
Holdtime : 139 sec

Version :
Cisco Internetwork Operating System Software
IOS (tm) C2600 Software (C2600-JSX-M), Version 12.2(26c), RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2007 by cisco Systems, Inc.
Compiled Mon 30-Jul-07 18:03 by ccai

advertisement version: 2
Duplex: half
Management address(es):

DR_Switch#

This is configuration of the interfaces...

(2610 router)

interface Ethernet0/0.1

encapsulation dot1Q 1 native

ip address 192.168.0.1 255.255.255.0

(2950 switch)

interface Vlan1

ip address 192.168.0.2 255.255.255.0

no ip route-cache

________________________________________________

Here is what i did to troubleshoot connection:

DR_Router#conf t

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

DR_Router(config)#in e0/0

DR_Router(config-if)#ip address 192.168.0.1 255.255.255.0

DR_Router#ping 192.168.0.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.0.2, timeout is 2 seconds:

.!!!!

DR_Router#conf t
Enter configuration commands, one per line.  End with CNTL/Z.
DR_Router(config)#in e0/0
DR_Router(config-if)#no ip address

DR_Router(config)#int e0/0.1

DR_Router(config-subif)#encapsulation dot1Q 1 native
DR_Router(config-subif)#ip address 192.168.0.1 255.255.255.0

DR_Router#ping 192.168.0.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.0.10, timeout is 2 seconds:

....

No result.... CAn you help me with this problem?

[kcnajaf]

Hi Dmitriy,

Try removing the "native" command from the router configuration and ping.

conf t

int e0/0.1

no encapsulation dot1Q 1 native

encapsulation dot1Q 1

Regards

Najaf

[XIE YAO]

additionally, make sure on your switch side, the interface(F0/2) must be set to trunk with "sw mo tru & sw tr en do"

[Dmitriy Rybkin]

I've tried to remove native from encapsulation command and interface F0/2 on the switch is set up as a trunk (dot1Q). No success. I will try to remove vlan files from flash on the switch and the router later on today and create vlans again, maybe thats some sort of a glitch. I dont see any other reasons for it not to work.

[kcnajaf]

Hi Dmitriy,

Look at this

Your first Ping

DR_Router#ping 192.168.0.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.0.2, timeout is 2 seconds:

.!!!!

Your second Ping

DR_Router(config-subif)#ip address 192.168.0.1 255.255.255.0

DR_Router#ping 192.168.0.2

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 192.168.0.10, timeout is 2 seconds:

....

For your second ping to 192.168.0.2 and ICMP request is send to 192.168.0.10...Check why is this happening on first place and that would nail the problem down

Regards

Najaf

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