03-26-2013 10:49 AM - edited 03-07-2019 12:29 PM
Hello forums
I have a question to the 3-layered network hierarchy model of Cisco concerning routing.
Core: fast packet switching, no routing function
Distribution: routing
Access: End devices
I build up the szenario shown in the attached image.
There are two sites in different cities.
C1 = core switch
D1 & D2 = distribution switch
A1 & A2 = access switch
All connections between switches are configured as trunk, allowing VLAN10 and 20 to pass.
PC10 & PC11: VLAN10 (Students)
PC20 & PC21: VLAN20 (Teachers)
Now my question:
On which distribution switch would you do the inter-vlan-routing??
Of course, the computers only can have ONE default gateway configured.
If you use D1, then traffic from PC11 to PC21 have to pass all the way to the other city - not really efficient.
Or is there anything like an "active/active HSRP" setup that BOTH distribution switches are used for inter-vlan routing.
Best regards and thanks in advance,
Lukas
03-26-2013 03:20 PM
Hi
U can cinfigure one dist switch to be active for one vlan and standby for the other by this u can have load balancing of traffic
Sent from Cisco Technical Support Android App
03-26-2013 05:25 PM
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Normally, you would NOT pass the site VLANs between your two sites. You would route on your L3 switches. Newer designs would normally also route in your core and some of the newer designs would extend routing to your edge. (In your topology, however, you show the core and access as L2, and distribution as L3.)
If your distribution to core uplinks were routed, you could reuse the same VLAN numbers as each site, but this would avoid spanning the VLANs between sites.
If you do share the VLANs across the sites, some clients' gateway might be at the other site, which as you note, is inefficient. (Which is a good reason why to avoid spanning L2 across WANs.)
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