Need help to choose a right router

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Oct 16th, 2009
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Any idea and help is appreciated.

Currently I have a 10MB Internet connection (ethenret straight from provider) and am going to upgrade this pipe to 100MB. The hand-off is Ethernet RJ45. While there are many choices, the cost is a concern (who doesn't have this problem these days?). I am not doing any BGP nor going to run any services on the router itself. I read somewhere saying I can even use a L3 switch, which I do have right now behind the existing ISP provided router(that 10MB) pipe. A new router is the preferred way and if L3 switch can be used that's greate too. Pros and Cons?

Thank you all.


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paolo bevilacqua Fri, 10/16/2009 - 02:22
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What is the expected traffic amount ? You can pretty much use any ISR router, sometime seems like there are too many types to chose from.

Joseph W. Doherty Fri, 10/16/2009 - 03:44
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Generally, routers offer features, L3 switches provide speed. So, for instance, for even just one 100 Mbps link, you might want at least a 3845 while a Catalyst 3560-8PC could easily handle the same load.


Yet, for Internet you note you won't run any services but what about NAT? I believe most L3 switches don't offer it but most routers would. What about a FW? Both devices provide basic ACLs but the router can be had with a FW feature set.


PS:

BTW, there are "Metro" L3 switches which offer some addtional features not usually found on most typical LAN switches.

paolo bevilacqua Fri, 10/16/2009 - 03:57
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I do not agree that one necessarily needs a 3845 to terminate a 100 Mbps internet circuit.


One reason, 100 Mbps is just a physical access speed but in reality you might be capped to 50, 30 or even less either by ISP policies, or simply not enough actual traffic.


Also, I would be very wary of using a L3 switch that does not have the full set of features most desired like Firewall, VPN termination, sophisticated NAT, voice, etc.


Anyway, that is one FAQ item and then each one chooses based on budget and his own parameters.


Attached, what cisco says about router performance.

ewong0088 Fri, 10/16/2009 - 04:10
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Thank you.

Actually, the 100MB is the, more or less, guaranteed speed. Less than that, I'll pull out the SLA and yell :)

In terms of L3 switch, I do have 3750G behind the existing router and F/W in between. I was misled from the beginning that a 2811 will work "well" by the ISP. Yes, I did read the performance guide. The bottom line is that I would like to get a router that will server my need but not to pay more for other features I know I am not going to need or use. The ISP suggested (comes clean?) Cisco 7204VXR (400 Processor) or Cisco 7204 VXR/225/FE. I think it's way over kill for what I am going to use the router for.

Thank you all.


paolo bevilacqua Fri, 10/16/2009 - 04:18
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A 7200 is not an overkill if you're going to handle close to 100 mbps bidirectional. That is actually the preferred choice of most corporate users doing "serious" networking.


Note that NPE-225 is seriously obsolete by today, and NPE-400 can be had cheaply. An NPE-G1 would have a much longer technological life.

ewong0088 Fri, 10/16/2009 - 04:26
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Thank you.


Any ballpark number on this one as mentioned? "NPE-400 can be had cheaply"


Glad that I ask the question here.



paolo bevilacqua Fri, 10/16/2009 - 04:33
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Check the popular auction site, there are many reputable dealers competing for business.


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Joseph W. Doherty Fri, 10/16/2009 - 07:22
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For 100 Mbps Ethernet, for minimum size packets, requires 148,810 pps. Duplex then would require 297,620. The NPE of the 7200 series correspond with their PPS rate, so "technically" a NPE-300 or faster would be needed to guarantee line-rate for any packet size.


Do keep in mind, you often need to have some extra CPU cycles for "other stuff". Larger packets sizes (much) reduce the required PPS rate, although don't assume a router will proportional scale (most, though, can support more "bandwidth" as packet size increases).


For reference the 3845 I mentioned (as seen in Paolo's attachement) provides 500,000 PPS.

Joseph W. Doherty Fri, 10/16/2009 - 07:28
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"I do not agree that one necessarily needs a 3845 to terminate a 100 Mbps internet circuit. "


Nor do I, although the reason I recommended it "as least", pretty certain it would be safe bet (similar to your mention of a NPE-G1). A smaller ISR might work just fine, although we know from later posts that a 2811 doesn't. Something like a 2851 or 3825 might be "just right".


[edit]

If truly nothing but routing is needed, and without full Internet BGP tables, the least expensive option would likely be a small L3 switch.

paolo bevilacqua Fri, 10/16/2009 - 07:34
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Joseph, I see your point, on the other hand I'm 100% sure that if I was to put a L3 switch as "internet router" into one of my accounts, one week later I would have to replace it with a true router, because it can't do [insert nice feature here] to which we are all well used.

ewong0088 Fri, 10/16/2009 - 07:48
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Thank you all.


I talked to one of our vendors and he suggested either:

(1) ME3750 with IP Services Image

or

(2) 7201


I wish I had checked the router performance guide earlier, instead of believing what the ISP says. How naive I was.

Thanks.

paolo bevilacqua Fri, 10/16/2009 - 07:57
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Do you do or plan to do GRE / IPsec tunnels ? A very common occurrence / that puts the 3750 out of the game. And there are many more.


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ewong0088 Fri, 10/16/2009 - 08:12
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I am not planning to do GRE or IPSEC tunnel on this (whatever form it will be) device. IPSEC will be on the F/W behind this new device.


Thanks.

paolo bevilacqua Fri, 10/16/2009 - 08:27
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So what the router ultimately does for you ?

You could connect the ISP handoff straight to FW.


Then, in most cases a router can replace a FW, but that's another matter.

Joseph W. Doherty Fri, 10/16/2009 - 08:15
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From what you've described, unsure the ME3750 provides you anything else that you need vs. a basic (small and "inexpensive") 3560, but performance wise, it certainly should deliver (as should almost any L3 switch). (Also unclear why the suggestion for the IP Services image, but we haven't discussed what else you need this device to do. This might also be true of software router, i.e. which IOS feature set might be necessary.)


The 7201 would be fine, although so should the 7301. Both have the features and performance, however you might sill inquire about 2851, 3825 and 3845.

ewong0088 Fri, 10/16/2009 - 08:20
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I am trying to upgrade bandwidth only, not adding service(s). Let's look at it this way. Right now, since the router on the 10MB is provided by the ISP, my F/W uses it as a gateway to get to the outside world. After ungrading, it will and should be the same. The only difference is now I have to cough up big $ to get a router or for less a ME3750 L3 switch if in fact it will work. Can't believe a 7201 costs over $20 grands!

Thanks.

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