Failover how much complexity will it add?
Seth Mattinen
sethm at rollernet.us
Mon Nov 9 17:23:41 UTC 2009
adel at baklawasecrets.com wrote:
> Actually thinking about this, I still need to understand the implications of not taking a full routing table to my setup. So what is the likely impact going to be if I take partial instead of full routing table. Would appreciate any feedback on this. My organisation is only looking at using BGP as a means of failover between two separate upstream ISPs. We are not an ISP.
>
Some Cisco L3 switches should support this fine. A 3560 or 3750 can
speak BGP and route at line rate as long as your total number of routes
will fit in its TCAM space. Ask your upstreams how big a partial feed
from them is.
"desktop routing" template:
The selected template optimizes the resources in
the switch to support this level of features for
8 routed interfaces and 1024 VLANs.
number of unicast mac addresses: 3K
number of IPv4 IGMP groups + multicast routes: 1K
number of IPv4 unicast routes: 11K
number of directly-connected IPv4 hosts: 3K
number of indirect IPv4 routes: 8K
number of IPv4 policy based routing aces: 0.5K
number of IPv4/MAC qos aces: 0.5K
number of IPv4/MAC security aces: 1K
If you ever need IPv6 it gets smaller:
number of unicast mac addresses: 2K
number of IPv4 IGMP groups + multicast routes: 1K
number of IPv4 unicast routes: 3K
number of directly-connected IPv4 hosts: 2K
number of indirect IPv4 routes: 1K
number of IPv6 multicast groups: 1.125k
number of directly-connected IPv6 addresses: 2K
number of indirect IPv6 unicast routes: 1K
number of IPv4 policy based routing aces: 0
number of IPv4/MAC qos aces: 0.5K
number of IPv4/MAC security aces: 1K
number of IPv6 policy based routing aces: 0
number of IPv6 qos aces: 0.625k
number of IPv6 security aces: 0.5K
Anything in Cisco land that can hold two full tables in hardware and can
do line rate is going to be hideously expensive.
~Seth
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