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L3 Full redundency issue

Hello everyone,

I have setup two layer 3 switch(3560),now there is a doubt how can i track my interface which is connected to ISP router,if somehow connectivity between L3 switch and router disturb then how traffic will move to another switch..diagram is given below.

Now here if uplink between sw1 to router gets down how traffic will move to another switch to firewall???

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Cisco Employee

L3 Full redundency issue

Sachin,

When the interface between switch and router goes down, switch will clear all MAC address associated with that port. In this case, the MAC address of Router (gateway) will be cleared. So any further traffic with destination MAC as router address will be flooded to all ports (normal L2 behaviour) till it learn the details via otehr port.

HTH,

Nagendra

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L3 Full redundency issue

i am assuming you are using something like HSRP in the switch pair for FHR and act as the default gateway for the host connected to the switch

if you need your traffic out to use the router as the primary path and the firewall as the secondary path you need to use floating static route with IP SLA in the switches

http://www.cisco.com/en/US/docs/ios/12_3/12_3x/12_3xe/feature/guide/dbackupx.html

http://www.firewall.cx/cisco-technical-knowledgebase/cisco-routers/813-cisco-router-ipsla-basic.html

hope this help