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3825 vs 3845: told the former won't do full DS3?

we are ready to start an MPLS migration from frame. We will have a 12MB DS3 circuit here at HQ. I was ready to place an order for a 3825 when the IT guys at one of our sites was told by a Cisco re-seller that if we go to a full DS3 a 3825 won't handle it. We don't intend to do MPLS on our routers but continue to do IP (eigrp). This guy also seemed to suggest that if we want to get into video and the QOS that we would want with it that we would then want to do MPLS on our routers and that would also require more power than a 3825 could deliver.

i've never done this before nor have we done any video (we're a constantly cash-poor non-profit and we move slowly)


#1: can a 3825 handle a full DS3

#2: what' the story with doing MPLS on my routers. When does one do that if ever?

#3. does streaming video (or using VOIP) require more power in the router?


Re: 3825 vs 3845: told the former won't do full DS3?


Answers to your questions

#1. The 3825 is rated for a throughout of 179Mbps - it could handle 4 DS3s !!. So your information is not quite correct. A 3825 will handle a DS3 perfectly well, particularly with the kind of traffic you have.

#2. MPLS is used by a lot of carriers - it allows you to do things such as L2 VPNs, L3 VPNs, and traffic engineering. Not too many enterprises out there have a need for it. There is no requirement for MPLS in order to do QoS and video.. you can do that just as well without MPLS (and with a good deal less complexity)

#3. Streaming video will increase the amount of traffic passing through the router (and so will VoIP) but the 3825 is perfectly capable of handling that for the kinds of traffic you are intending to pass through it.

Hope that helps - pls rate the post if it does.



New Member

Re: 3825 vs 3845: told the former won't do full DS3?

tnx for your reply. Is there someplace that the 179Mbps is noted? Also, a source we are working with sent me this:

"We need to go with the 3845. See below on a cut/paste from Cisco's technical marketing materials.

Cisco 3825

Full rate T3/E3 with no services

Large and regional branch offices

Cisco 3845

Full-rate T3/E3 with concurrent services

Large and regional branch offices

"Services" would be anything that has to do with Voice, Video, or Security.

Have you seen a 3825 in action and if so with streaming.

Frankly, this is confusing to me

VIP Purple

Re: 3825 vs 3845: told the former won't do full DS3?


in that context, does anybody know what ´subrate´ means exactly ? Obviously less than full rate, but what is the upper limit for a subrate T3/E3 ? There have been a couple of posts in the forum before inquiring about that, but I guess there has not been a conclusive answer, yet...

Thanks for the help in advance.



Re: 3825 vs 3845: told the former won't do full DS3?

Here's the link to performance information:

I find it extremely hard to believe that the 3825 will not handle streaming video...I've used 3825s as a multi-access customer edge router without any real problems.

It all comes down to how much traffic you are going to push through it. As with any router, the more traffic you have, the more grunt you will need.



Re: 3825 vs 3845: told the former won't do full DS3?

Please check the following link. It will give us an idea of what Cisco implies by services

If the video streaming and voip will just look like data to the router, then there is no reason why the 3825 should not handle it. But if for example, the 3825 would also be used as the Call Manager Express, then there might be issues, with it also concurrently routing E3/T3 volume of traffic. Unfortunately, while we have the performance figures for data throughput, i.e. the maximum packet switching ability of the router, as well as its backplane, we do not have the amount of memory or cpu cycles tha these extra services take. Some of these services could be cpu intensive (NAT for one is known to be CPU intensive and increases with traffic).

I will advice therefore that you consider the present and future need for the router. If it will never be needed to add extra services to the router, then you could go for 3825. But if you presume, that the router could be used to offer other services, either now or in the future, then I advice the 3845.

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