paolo bevilacqua Thu, 07/02/2009 - 12:28
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The way you posed the question, no answer can be given.


What is that you call lan extension in first place ?


Also you need to specify what is your primary mean of connectivity, and which one the backup ?



CCDECCDE9 Thu, 07/02/2009 - 12:49
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I mean fibre ethernet connection between TWO SITES geographically separated by cisco3750 layer 3 switches on each side.Currently,I have one link in place and looking for an anothe one so that high availability is achieved for connectivity purposes.One site has servers and othe rsite has users.

Giuseppe Larosa Thu, 07/02/2009 - 12:54
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Hello Mohammed,

if the current inter-site link is a L3 link just add another one and use a routing protocol of your choice EIGRP or OSPF to route traffic in between.


if the link is L2 only just add a L2 link in the same vlan/sets of vlans (if a trunk) and you have STP managing the redundancy for you


Hope to help

Giuseppe


Jon Marshall Thu, 07/02/2009 - 12:56
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Mohammed


Is the existing link a routed or a L2 link at the moment.


Either way first you need


1) another fibre connection

2) another pair of switches


then if L2


you can simply allow one of the L2 connections to block. Alternatively you could stack the new 3750 switches and then run a cross stack etherchannel from one pair of switches to the other pair


if link is L3


simply add the other link on the second pair of switches and your routing protocol will use both paths.


Jon

Jon Marshall Thu, 07/02/2009 - 13:37
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The LAN facing links yes it would make sense to use HSRP.


But the inter-site facing links, no you do not need HSRP.


Jon

CCDECCDE9 Sun, 07/05/2009 - 16:44
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one site has one cat4006 and other site has one 3750 .Fibre is connecting both these sites.Each switch on these sites using one of their ports with ip address to link them .Please advise the best way to achieve redundancy between these sites


Thnaks

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