Can Cisco 3925 (old model) support 150 Mbps of Internet BW?

[mwaqarkhan]

Hello,

We have recently provided the bandwidth upgrade from 100 Mbps to 150 Mbps to customer's existing Cisco 3925 router.

As per the Cisco recommendation, it is mentioned this model support 100 Mbps WAN bandwidth, but as I know and read somewhere that this is not hard limitation and if the router is only used for this WAN purpose without any overheads on it, it should be able to support more than that.

But what we experienced is different, and the router is not taking the upgraded BW. Can anyone suggest what could be the problem?

Thanks,

Muhammad

[balaji.bandi]

here is the performance report ( attached)

good thread  to confirm :

https://community.cisco.com/t5/routing/throughput-router-3925e/td-p/1908167

[mwaqarkhan]

Thanks brother for sharing this. 

Even as per this performance report, the WAN Speed should be able to exceed 150 Mbps especially when no other services are used on the router.

Then why we are unable to upgrade the WAN BW from 100Mb to 150Mb and why the router is not supporting it? 

Or the customer/field engineer is just misleading us.

[marce1000]

 - The document and part I mentioned is rather clear, and or not supporting it just because of being that model , including limitations.

 M.

[balaji.bandi]

Can you post the configuraiton, where your provider link connected ? Gig or FE ?

how are you testing FE or GIG ?

[marce1000]

 - Ref : https://www.cisco.com/web/AP/partners/ANZ_PE/borderless_network/Cisco_routerperformance.pdf

   >...

   • The Cisco 3900 Series enables deployment in high speed WAN
environments with concurrent services enabled (150 Mbps with Cisco
3945 and 100 Mbps with Cisco 3925).

 M.

[mwaqarkhan]

Thanks Marce and you are right, and I know that WAN recommended BW is 100 Mbps.

but my question here is that, if there is no other service running on the router, cannot it support 200 Mbps?

Is it a hard limitation or it is based on resources availability. As per the performance report, it shows that it can go much higher if we are not running multiple services.

[Joseph W. Doherty]

Indeed, the 100 Mbps (duplex) is a Cisco recommendation, the router, depending on traffic mix and router configuration, can do more, sometimes even much more.  Cisco documents the 3925 forwarding up to 6.9 Gbps (non-duplex, best possible case)!  NB: don't go assuming though, such bandwidth performance (i.e. 6.9 Gbps) is reasonable for "real world" traffic.

It would help if you would describe how this router can not handle 150 Mbps when it could 100 Mbps.  I.e. CPU usage, drops, etc.?

Further, I wonder, was the prior 100 Mbps provided on a physical FE link and the 150 Mbps provide via a gig physical link?  If such a case, a gig link could burst traffic too fast for the 3925 to handle, which would not be the case with a FE link.  Even if the physical link was gig for 100 Mbps, how was 100 Mbps (and the new/now 150) "enforced" on a gig link?

[mwaqarkhan · Accepted solution]

I'll try to investigate it further and get back with results, thanks for your response.