Data Centre BGP Router - will a SUP32 be OK for full internet routes?

Unanswered Question
Mar 18th, 2009


We are an ISP and opening a new data centre soon. Our current data centre uses C4507's with SUPIV's and 7206VXR/NPE-G2's.

Based on the currently CPU and bandwidth usage (CPU averages 45% , with BW around 500Mbs) we know that the 7206/NPE-G'2 will not suffice for our new data centre which will be larger than our current. The NPE-G only supports up to 1Gbs throughput anyway.

We are looking for cost-effect options for BGP/Internet transit routers for our new DC. We need to support full internet routes (135,000 networks and 146,000 subnets based on info from our existing routers) and eBGP prefixes from two providers (around 275,000 prefixes from each) and four iBGP sessions (around 250,000 prefixes from each). We also need to support up to 4Gbs of routing performance for this transit traffic (ideally 5 or 6Gbs to allow for future growth).

The Cisco datasheets always state the max number of routes, they don't state anything about prefixes which I thought should be a consideration.

I know the SUP720-3BXL would fulfil our requirements easily but it's a massive cost. So would the SUP32 be sufficient for our requirements?

Any advice from anyone using the SUP32 in their network for the purpose above would be appreciated.



I have this problem too.
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Giuseppe Larosa Wed, 03/18/2009 - 03:44

Hello Chris,

you need a Sup 720 3BXL or better to handle two Internet full BGP tables.

sup32 MSFC2A has 1 GB RAM but compares to MSFC2 for other parameters


If you need to upgrade from a C7206VXR NPE-G2 you may consider to use an ASR 1004 or ASR 1006 that can have a 20 Gbps throughput and should cost less then a C6500 with Sup 720 3BXL


Hope to help


Joseph W. Doherty Wed, 03/18/2009 - 05:17

Like Giuseppe, don't believe a sup32 would be suitable.

Giuseppe's suggestion of the ASR would seem best for the 4 to 6 Gbps. However, if the load might not be that heavy, there's another router that falls between the -G2 and the new ASRs, which would be the 7304 with NSE-150. This router tops out at about 3.5 Gbps.

lamav Wed, 03/18/2009 - 07:37


According to the statistics from the Cisco webpage, the SUP-32 has the same memory capacity that the SUP-720s have in terms of SP NVRAM, SP DRAM, SP onboard Flash and removable memory, the most pertinent of them being the DRAM, since the question involves the SUP-32s ability to hold 2 full Internet routing tables.

So why is the SUP-7203BXL necessary?

Take note, Im not challenging you, just asking.


Giuseppe Larosa Wed, 03/18/2009 - 07:53

Hello Victor,

I remember a thread of someone trying to upgrade a sup 720 3B to have 1GB memory.

However, being this a multilayer switch is important to verify how many routes can be handled in the CEF tables.

Someone correctly pointed out that also the SP memory has to be upgraded to achieve the desired result.

And here the limitation should appear.

Hope to help


lamav Wed, 03/18/2009 - 08:25

Im not sure I understand what you're saying.

Joseph W. Doherty Wed, 03/18/2009 - 17:51

My thinking on the sup32 vs. XL, the OP mentions two external full Internet routes (as you also noted), but it also noted four iBGP sessions, each 250K prefixes. Unclear where they come from, but if they exist, they alone would need another gig.(?)


Victor, how have you been? You haven't been as active posting as you used to be.

lamav Wed, 03/18/2009 - 18:29

Hey, Joseph!

Good "seeing" you. I always love to read your stuff.

I've been OK, just real busy with my client and have been traveling, too.

I do miss the discussions on this board, so when there is a bit of a slow down, I try to jump on and learn a few new things. :-)

Hope all is well with you.

Thanks for asking....


ccpagel Thu, 03/19/2009 - 01:01


Thanks for all responses to my post.

The four iBGP session come from three existing BGP routers at our existing Data Centre and a second BGP router at the new Data Centre (there will be a pair of routers).

So far I'm getting that the SUP32 would not be suitable so does anyone have any experiance of the ASR and would this be suitable? In our case the ASR would purely be used as a BGP router.



Giuseppe Larosa Thu, 03/19/2009 - 04:35

Hello Chris,

I haven't a direct experience up to now. My customer is considering to evaluate the platform.

performance data in the signalling plane are impressive:


• Scalability to 1,000,000 IPv4 or 250,000 IPv6 routes (RP1)

• Scalability to 4,000,000 IPv4 or 2,000,000 IPv6 routes (RP2)

• BGP RR Scalability to 25,000,000 IPv4 or 24,000,000 VPN IPv4


Up to now in the forums some problems have been reported about:



the way it uses etherchannel (vlan based)

Hope to help


ccpagel Fri, 03/20/2009 - 01:54


again thanks for the responses.

The ASR looks good and looks as though it would fulfil our requirements however costs is an issue again - we may as well buy a SUP7203BXL.

I think on this occasion we will have to look alternatives outside Cisco.

Thanks again



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