3560 Redundancy

Answered Question
Jan 15th, 2009

Hi Guys,

I have a new 2x 3560, do you have any suggestion on how can I make this redundant? Like you will just see 1 node for this two switches. I have configured an etherchannel on it but it seems it is not working.

interface GigabitEthernet0/1

channel-group 1 mode auto

switchport mode trunk

!

interface GigabitEthernet0/2

channel-group 1 mode auto

switchport mode trunk

Any help is very much appreciated. Thanks in advance.

Cheers!

I have this problem too.
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Correct Answer by Jon Marshall about 7 years 10 months ago

Irvine

Can you post full configs for both switches.

if you want to connect the 2 switches togther with an etherchannel trunk

SW1(config)# int range gi0/1 - 2

SWI(config-if)# switchport

SWI(config-if)# switchport trunk encapsulation dot1q

SWI(config-if)# switchport mode trunk

SW1(config-if)# channel-group 1 mode on

do same config as above for SW2

Connect the 2 switches together on gi0/1 & 2.

3560 will run HSRP/GLBP. This is used for gateway redundancy. So an example

SW1

int vlan 10

ip address 192.168.5.2 255.255.255.0

standby 10 ip 192.168.5.1

standby 10 pri 110

standby 10 preempt

standby 10 auth

SW2

ip address 192.168.5.3 255.255.255.0

standby 10 ip 192.168.5.1

standby 10 pri 100

standby 10 auth

then any client in vlan 10 is given the default-gateway of 192.168.5.1

Jon

Correct Answer by Tshi M about 7 years 10 months ago

Hi,

what do you get when you do:

sh ether sum

what do you see in the log?

At the very basic, i will have:

po1

switchport trunk encapsulation dot1q

switchport mode trunk

g0/1

switchport trunk encapsulation dot1q

switchport mode trunk

channel-group 1 mode desirable

g0/2

switchport trunk encapsulation dot1q

switchport mode trunk

channel-group 1 mode desirable

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Jon Marshall Thu, 01/15/2009 - 06:56

Irvine

What do you mean by redundant. Do you mean connect them togther with etherchannel and perhaps run HSRP between the 2 switches ?

Can you post output of

"sh etherchannel summary" &

"sh int trunk"

from both switches.

Jon

gagamboy15 Thu, 01/15/2009 - 07:05

Hi Jon,

Yes, you're right. But I don't think 3560 supports HSRP, Is there any protocol or way for redundancy.

Please see attachment. Thanks.

Attachment: 
Correct Answer
Jon Marshall Thu, 01/15/2009 - 07:14

Irvine

Can you post full configs for both switches.

if you want to connect the 2 switches togther with an etherchannel trunk

SW1(config)# int range gi0/1 - 2

SWI(config-if)# switchport

SWI(config-if)# switchport trunk encapsulation dot1q

SWI(config-if)# switchport mode trunk

SW1(config-if)# channel-group 1 mode on

do same config as above for SW2

Connect the 2 switches together on gi0/1 & 2.

3560 will run HSRP/GLBP. This is used for gateway redundancy. So an example

SW1

int vlan 10

ip address 192.168.5.2 255.255.255.0

standby 10 ip 192.168.5.1

standby 10 pri 110

standby 10 preempt

standby 10 auth

SW2

ip address 192.168.5.3 255.255.255.0

standby 10 ip 192.168.5.1

standby 10 pri 100

standby 10 auth

then any client in vlan 10 is given the default-gateway of 192.168.5.1

Jon

Tshi M Thu, 01/15/2009 - 07:21

Your first mentioned that both g0/1 and g0/2 are part of the po1 ether but your attachment shows that g0/1 belongs to po1 and g0/2 belongs to po2.

Correct Answer
Tshi M Thu, 01/15/2009 - 06:58

Hi,

what do you get when you do:

sh ether sum

what do you see in the log?

At the very basic, i will have:

po1

switchport trunk encapsulation dot1q

switchport mode trunk

g0/1

switchport trunk encapsulation dot1q

switchport mode trunk

channel-group 1 mode desirable

g0/2

switchport trunk encapsulation dot1q

switchport mode trunk

channel-group 1 mode desirable

gagamboy15 Thu, 01/15/2009 - 07:41

Hi Guys,

Thanks for the feedback. It seems that I misconfigured the port channel mode and PO1 and PO2 group for both switches.

By the way is it advisable to do port-channel mode ON on both switches? or should I stick to auto-desirable?

Is there any another way to do redundancy aside from HSRP?

Thanks to you guys!

Cheers!

Tshi M Thu, 01/15/2009 - 07:55

I will use mode on prevents negotiation and might a safe bet.

regards

Carlitos Carne Sat, 01/17/2009 - 17:28

Using 'port-channel mode on' means just what it says; there will be no negotiation. I use it because it is quicker. If you use it, you must always be certain that all ports you intend to physically connect are correctly configured BEFORE connecting them. Otherwise, you could wind up with a looping condition that could do some pretty nasty things on your network.

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