Memory for iBGP and 500 routes

Answered Question
May 19th, 2009

Hi all,

I am searching for memory requirements for iBGP on a 3750 ip-service ios and 500 routes.

Any suggestion?

Regards Jan Rockstedt

I have this problem too.
0 votes
Correct Answer by Giuseppe Larosa about 7 years 8 months ago

Hello Jan,

main memory is not a problem as noted by Paolo.

You can exstimate 1 KByte memory for each prefix (including BGP and CEF).

Being a multilayer switch it is very important that all prefixes can be hosted in the TCAM table (this means efficient L3 forwarding).

TCAM usage depends on deployed strategy called SDM template

Be aware of the following:

see table 8-1

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/configuration/guide/swsdm.html

With a routing SDM template TCAM can handle 6,000 MAC address and 20K ipv4 routes.

change of SDM template is effective only after reload.

And you need an IP services image to run BGP

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/configuration/guide/swiprout.html#wp1226539

You should be fine.

Hope to help

Giuseppe

Correct Answer by Paolo Bevilacqua about 7 years 8 months ago

No more memory than default is needed.

Beside, 3750 memory is not expandable.

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Overall Rating: 4 (3 ratings)
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Correct Answer
Paolo Bevilacqua Tue, 05/19/2009 - 08:52

No more memory than default is needed.

Beside, 3750 memory is not expandable.

Correct Answer
Giuseppe Larosa Tue, 05/19/2009 - 09:15

Hello Jan,

main memory is not a problem as noted by Paolo.

You can exstimate 1 KByte memory for each prefix (including BGP and CEF).

Being a multilayer switch it is very important that all prefixes can be hosted in the TCAM table (this means efficient L3 forwarding).

TCAM usage depends on deployed strategy called SDM template

Be aware of the following:

see table 8-1

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/configuration/guide/swsdm.html

With a routing SDM template TCAM can handle 6,000 MAC address and 20K ipv4 routes.

change of SDM template is effective only after reload.

And you need an IP services image to run BGP

http://www.cisco.com/en/US/docs/switches/lan/catalyst3750/software/release/12.2_46_se/configuration/guide/swiprout.html#wp1226539

You should be fine.

Hope to help

Giuseppe

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