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marmar_gh60
Beginner

Cisco 3560 for BGP

Hi

my company has recently bought two cisco 3560 switches which can do BGP.

I have suggested the use of default route based on what I have read in the document and I don't think these routers can handle to store the routing tables from the ISPs.

I belive the plan is to use these two as active passive and then do multihoming to two different ISPs.

Could someone help me find out solutions to configure these?

1.I'm not sure how the active-passive is going to work.

2.I'm not sure if the memory can handle the ISP's routing table or/and how to configure the default routes (or is it better to use the AS_Path filters)?

3. is the memory upgradable? (I could not find any documents regarding the memory upgrade and if it is possible)

4. Any other good suggestions are appreciated.

This is my first serious project and I really don't want to disappoint them.

Thanks in advance.

Mary.

2 REPLIES 2
dixho
Frequent Contributor

There are two forwarding engine for 3560: hardware and software.

You should design the network to use the hardware forwarding engine switch/route traffic. Please see Table 7-1 at the following URL:

http://www.cisco.com/en/US/partner/docs/switches/lan/catalyst3560/software/release/12.2_55_se/configuration/guide/swsdm.html

The TCAM (hardware forwarding engine for 3560) can handle up to 8K indirect routes. Thus, it cannot handle all Internet routes. The size of TCAM is not upgradable. If you want to hold the full internet table, you should use CAT6500.

If you try to load the full Internet table on a 3560, 3560 will switch traffic by the software path, which has significantly lower throughput. It will also run high CPU. Not the way 3560 is design for.

Hi

Thanks for you reply. Although I could not access the URL that you included for some reason.Do you think you could provide the table you were talking about in any other form?

I researched more since I posted this and I agree, the switch can't handle all the routing tables.

I need to figure out rules and policies to avoide our AS to be a transit AS between two ISPs.

Thanks

Mary