Etherchannel From Core 2-3 Not Working

[up2014497]

Hi, I am having issues configuring etherchannel. from core 1 (G1/0/1-2) to core 2 (G1/0/1-2) i managed to configure it no problem. But i then tried to configure another 1 from core 2 (G1/0/3-4) to core 3 (G1/0/1-2). Sorry if this is something really basic...

[Martin L]

Etherchannels seems to be fine!  (P) (P) from Core 2; there is issue with dup address, see 

Core2#

Core2#%IP-4-DUPADDR: Duplicate address 10.1.24.130 on Vlan28, sourced by 0060.705D.08D0

Core2#sh etherchannel s

Flags: D - down P - in port-channel

I - stand-alone s - suspended

H - Hot-standby (LACP only)

R - Layer3 S - Layer2

U - in use f - failed to allocate aggregator

u - unsuitable for bundling

w - waiting to be aggregated

d - default port

Number of channel-groups in use: 2

Number of aggregators: 2

Group Port-channel Protocol Ports

------+-------------+-----------+----------------------------------------------

1 Po1(SU) LACP Gig1/0/1(P) Gig1/0/2(P)

2 Po2(SU) LACP Gig1/0/3(P) Gig1/0/4(P)

Core2#

Regards, ML
**Please Rate All Helpful Responses **

[up2014497]

Sorry its just when i try to ping to test connectivity from core switch 3 I am unable to ping the other core switches/other devices. When i do the show int trunk, it says no vlans are allowed in management domain. Im not sure if that has anything to do with the issues i am having. Thanks...

[up2014497]

[Martin L · Accepted solution]

Ping fails because of SVI is in down state on Core3; This is normal as switch performs SVI state checks by default; you could disable such check on real switch but not in PT (PT is just a simulator; some commands are missing and IOS behavior is not the same);

 To get SVI interface x in UP state; a) switch must have vlan x in database, b) vlan x must be allowed on trunk ports; c) switch must have at least 1 access port in such vlan x and such port must be active (not shutdown). and of course SVI must have valid IP assign to it and be no shut sate.

Please, add vlan 10 on switch3, If SVI is still down, add PC in access vlan x on core 3 and look for show ip interface brief to see SVI x UP UP state; then u can ping it;  

Note: in case of PT, it seems that only having vlan 10 in database fixes the issue - unlike real switch IOS

Regards, ML
**Please Rate All Helpful Responses **