06-13-2006 10:40 PM - edited 03-03-2019 03:38 AM
Hi All!
yesterday;i've configured a switch with 4 port uplink(EtherChanel)in the side access switch,the channel mode is desirable but by mistake the persom who configured in side core mode chanel is on;then when accees switch startup we have received duplicate ip address.loop,error,and all the access switch down.what is the problem here?what is happen;when we turnOff this switch every thing is fine
10xs
Ali
10xs
Ali
06-13-2006 10:46 PM
Hi
the config was like this in the access side:
interface GigabitEthernet0/25
switchport trunk encapsulation isl
switchport mode trunk
channel-group 5 mode desirable
........................................
interface GigabitEthernet0/26
switchport trunk encapsulation isl
switchport mode trunk
channel-group 5 mode desirable
....................................
interface GigabitEthernet0/27
switchport trunk encapsulation isl
switchport mode trunk
channel-group 5 mode desirable
...................................
interface GigabitEthernet0/28
switchport trunk encapsulation isl
switchport mode trunk
channel-group 5 mode desirable
..............................................
interface Port-channel5
switchport trunk encapsulation isl
switchport mode trunk.
10xs for ur reply
Ali
06-13-2006 11:11 PM
ali look at this link :http://www.cisco.com/univercd/cc/td/doc/cisintwk/itg_v1/tr1923.htm#xtocid44
and read the table 23-4...may it will help you
regards
Devang
06-13-2006 11:40 PM
Hi Friend!
10xs for ur reply!this link didn't include something about my problem.did u faced like this?where the Expert like Ankur to help Me.
10xs Friend
Ali
06-13-2006 11:51 PM
Devang pointed out that a channel cannot be formed with the configuration desirable-on.
The information from table 23-4 tells you to use either desirable-desirable, desirable-auto or on-on to successufully form a channel.
As you did not supply the remainder of the switch configuration we cannot determine what caused the problems you mentioned.
It's verly likely that with four redundant paths between your core and access layer a loop occured.
Check your spanning-tree configuration and supply sufficient information for further assistance.
May I remind you that help is on best effort basis. We are not here to help you promptly, be patient and polite and you might get what you need.
--Leon
06-14-2006 12:03 AM
Hi
Sorry Friend!this the Second MOnth That i have working in Cisco Product!
1st)where i check the Spanning Tree?
2st)if the config on the access switch its desirable;and in the core(by mistake) the channel is on, make This big problem in the enterprise network.loop;servers no pingable?what can i do?
10xs
Ali
06-14-2006 12:09 AM
Hi Ali
As a quick fix disconnect u r ports which are used in u r channel.And try to verify u r STP topology.
show spanning-tree
As in the above posts confure ur channel to desirable-desirable it is recommnded to avoid problems like which occured in ur case.and try to check the cables for a possible UDLD problem.
Thanks
Mahmood
06-14-2006 12:18 AM
HI Mahmoud!
check the cables for a possible UDLD problem.what do u mean by this?
10xs
Ali
06-14-2006 12:44 AM
Cisco.com has a great documentation site: http://www.cisco.com/univercd/home/home.htm
For quick reference use Google: "UDLD site:cisco.com/univercd".
UDLD is used primarily on fiber optic linkd, to monitor bi-directional communication. In case of a transmit/receive failure a uni-directional connection occurs and will result into a L2 loop when redundant paths exist.
--Leon
06-14-2006 01:56 AM
UDLD: udld protocol allow for detection of unidirectional link condition on switch ports in situation where a link remain in up state but the interface not passing traffice...this is most offent in GBIC or interface, software malfunction, hardware faliure or other any behaviour...
UDLD is l2 protocol and used to determine the physical status of link...with udld, switch periodicaly send the udld protocol packets to its neighbor and wait for the echoed back before predetermined time...and if echo will not receive switch determines the linke to be unidirectional and shuts down the port...
hope this will help you
ali i am just try my best to help you nothing more...and yes ankur is expert and i respect him and his help, he also help me lot...
rate this post if it helps
regards
Devang
06-14-2006 02:54 AM
Hi devang!
10xs for ur reply,but PS Don't get me wrong.i have thanks every one help me.Devang;Ankur has a very good Description of the problem;and help how to fix it quikcly.
regards
Ali
06-14-2006 03:06 AM
hi ali,
thanks for complement...and ya i also get good help form netpro form...and yes i also would like to share knolege ...as i am also learn lots of thing...because i also find some good issue which help me to learn or troublshoot in my work...
thanks again
regards
Devang
06-15-2006 12:28 PM
I might be missing something here, but if the core side was set to "on" by mistake, then why was it an issue to get into one of the two switches and just make them the same? Either desirable or on. Wouldn't that have fixed it very quickly?
regards,
jeff
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