GLBP;STP

[alsayed]

Hhave a look to this scenario:

L3

SW1---------------SW2

ACCESS SWITCH LINK TOWARD--------SW1

TOWARD--------SW2

ACCESS SWITCH CONNECTED TO EACH DISTR.I NEED TO IMPLEMENT GLBP FOR GATEWAY LOAD BALENCY.I NEED THE CONFIGURATION OF THIS SCENARIO.ALSO HOW CAN STP CONVERGE;IF A ONE LINK FAILURE FROM THE ACCESS TO THE DISTRIBUTION.HOW CAN I CONFIGURE STP FORTHIS ISSUE

10XS FRO REPLY

ALI

[ankurbhasin]

Hi Ali,

Which switch do you have as distribution switch?

Regards,

Ankur

[alsayed]

HI ANKUR 10XS FOR UR REPLY!

I'WILL USE IN THE ACCESS SWITCH 3560G;

6509 DIST

ALSO 6509 ON THE CORE

ANKUR MY FRIEND;NO RISTRICTION ON THE BUDJET

10XS

ALI

[ankurbhasin]

Hi Ali,

Because you are connecting 2 distribution switches together, STP will block one connection to prevent layer 2 loop so even if you configure GLBP the STP convergence will take its own time 30-50 seconds to converge and GLBP may not give you a desired results.

So if you want STP convergence fast with GLBP gateway failover you have to tune the STP timers also.

Regards,

Ankur

[devang_etcom]

hi ankur,,,

will it be possible to solve the stp converge issue by deploying RSTP will it work better or not...?

regards

Devang

[ankurbhasin]

Hi Devang,

RSTP will work fine with a convergence time of 7-8 seconds but it depends on the port role assigned to the switch ports.

I haven't deployed or troubleshooted RSTP enviroment so not very sure of it can bring any more complexities in the network convergence with GLBP.

But if I have to design a network I will not connect the 2 distribution switch if I am implementing GLBP or HSRP to keep STP away. You can have STP root on HSRP active router and STP secondary root HSRP standby router and connect it via the access switch so that you can have STP as well as HSRP load balancing also.

Regards,

Ankur

[alsayed]

hi ankur 10xs for ur reply!

simple configuration for that scenario very much appreciated.but what about if one linke among the the 2 exiting link from the the access to each distribution fail!how can i configure stp to converge this issue?

10xs

[ankurbhasin]

Hi Ali,

To converge STP with GLBP you should set the STP timers on distribution switch as well as access switch as

spanning-tree vlan hello-time 1

spanning-tree vlan forward-time 4

spanning-tree vlan max-age 6

Cisco also recommend not to play around with STP timers mostly but if your requiremnet is something like this make sure you change STP timers on all the switches for STP consistency.

Regards,

Ankur

[alsayed]

HI ANKUR!

10XS FOR UR REPLY!

U HAVE A LINK OR DOCUMENT THAT U HAVE USED TO IMPLEMENT.CONFIGURE SUCH THAT PROJECT

10XS

[ankurbhasin]

Hi Ali,

I don't have a single link or any document which may have config for both GLBP or STP but indivisually you can have a link to look and understand both

with topology and config guides

For GLBP

http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122newft/122t/122t15/ft_glbp.htm

For STP

http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/12_1e/swconfig/spantree.htm#wp1065205

HTH, if yes please rate the post.

Ankur

[alsayed]

HI ANKUR

10XS FOR UR REPLY!

PS CAN U LIST TP ME A SIPLE CONFIG FR THAT SCENARIO:

1-ON THE 2 PORT OF THE ACCESS SWITCH THAT CONNECTED TO EACH DISTRI

2-ON THE 2 PORT OF EACH DISTRIBUTION

FOR BOTH:GLBP&STP

SIMPLE CONFIG ANKUR.

SORRY ANKUR

10XS

ALI