Cisco 2921 ISR for routing 100Mbps ISP internet?

[hinewwiner1234]

Okay I am new to here and have been reading reading posts here.

It seems that Cisco mentioned, in their data sheet of 2921 ISR, that it can support up to 50Mbps. However, from Google search, it says 2921 can handle 100Mbps with no problem.

I am planning on getting 2921 ISR in small office where only ~10 people are connected to it. And we do have two different line of 100Mbps ISP internet line  and wish to share them in the office.

I am confused why ~$2k router can not support 100Mbps where ~$100 consumer routhers like Linksys has no problem with handling that speed.  The reason why I am planning on 2921 is the rich feature like Voip solution (CME) it offeres.  I have several remote offices that needs to be connected with Voip phones. and I could go with UC500 series but it seems to me UC500 does not support IP Phone 9900 series... so...

So can someone tell me if 2921 ISR support 100Mbps?

Thank you so much!

[Roman Rodichev · Accepted solution]

2921 can handle up to 245Mbps throughput

[paolo bevilacqua]

100 Mbps is the physical access speed and doesn't means much in itself.

Try asking the ISP what is the actual speed that you can have to the internet, or use some speedtest tool, and let us know.

[hinewwiner1234]

I understand what you mean, but in my area I am actually getting 100Mbps from several speed test sites.

Thanks anyway!

[paolo bevilacqua]

That is the first time hear something like that, and I would love to see it first hand, especially for the upload speed.

Anyway, good for you then.

[Joseph W. Doherty]

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Posting

Cisco rates the 2921 at 352 Kpps for 64 byte size packets.  Since Ethernet requires 148.8 Kpps for 100 Mbps for 64 bytes size packets, 352 Kpps should handle 100 Mbps duplex, but this also assumes the router isn't supporting any services (and also usually assume all fast path processing).

Taking into account everything that you might want to do with traffic, from NAT, to firewall support, to QoS, Cisco recommends the 2921 for up to 50 Mbps.