WAN Bandwidth Perfomance - Cisco 3845

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Hi Team,

We are using Cisco 3845 Router with 300 Mb bandwith for Internet  from multuple ISPs  .

I want to know is it support more than 300 Mb throughput ? and what effect in my router.

Up to how many Bandwidth support in 3845 router and if exceed the bandwith througput limit then what effect occure in my router.

Please help me.

Thanks in ADV,

[jamie.grive]

Hi,

Do you know your average packet size spread? Are you using the 3845 to do any VPN (IPSEC) or any other integrated services on the ISR? These both will have a big effect on the total throughput capability.

Realistically I think the 3845 can do about 300Mbps depending on the above question it could be less.

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Hi Jamie,

We are not using any IPSEC VPN service.

We are using eBGP protocol mulihomed  and many subinteraces with service policy for bandwidth limit many clients with static routes.

In this case how many bandwith throuhput support without any effect in 3845 Router.

[jamie.grive · Accepted solution]

You are just using the platform for routing then it should cope with 250~300Mbps depending on packet size (smaller packets would mean less throughput - e.g. lots of Voice).

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Thanks Jamie,

But how to check my packet size are using in 3845 for your reference.

[Joseph W. Doherty]

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Posting

Well if you already have a 3845 in service, what does its CPU loading look like relative to different traffic loadings (for your traffic and with your configuration)?  You can roughly scale your bandwidth, for its CPU loading, remembering generally you don't want to exceed about 75%.

That said, in abstract a 3845 is rated at 500 Kpps for minimum size packets, which assuming all CPU was devoted to packet forwarding, 200 to 300 Mbps (aggregate - don't forget to half for two way).

In a later ISR performance white paper, the 2921 is rated at 479 Kpps, yet the router is only recommended for up to 50 Mbps of WAN bandwidth and the 2951 rated at 579 Kpps is only recommended for up to 75 Mbps.

Personally, I believe the 3845 is rather "safe" for up to about 100 Mbps (duplex).