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belushi
Premium Member
join:2000-11-08
Twinsburg, OH

belushi to nure

Premium Member

to nure

Re: RE: can a l3 switch with full dynamic protocol set

Depending on the device a layer 3 switch can absolutely be used as a router. That's pretty much the definition of a layer 3 switch. Obviously its ability to handle full routing protocols depends on the version and IOS in use. Generally enhanced image layer 3 switches like 3560s, 3550s, 4500s, 6500s to name a few can handle very robust routing protocols. Some of the switches even come with the options to install very robust WAM interfaces.

I almost hesitate to even call a 6500 a switch nowadays with all the different modules you can install into it. Cisco is making it kind of like an all encompassing device for routing, switching, firewall,IDS, IPS, voice, video, etc. The lines between devices are surely being blurred as time progresses.

nure
@imagefoundation.com

nure

Anon

Hi,thanks, when you say
"Generally enhanced image layer 3 switches like 3560s, 3550s, 4500s, 6500s to name a few can handle very robust routing protocols"
do you mean, that they can route between their interfaces.
because i thought 3550 can't
thanks
nure

belushi
Premium Member
join:2000-11-08
Twinsburg, OH

belushi

Premium Member

I thought you were talking about a switches ability to handle dynamic routing protocols like EIGRP, RIP, OSPF, etc. These switches can do it, but generally you need enhanced image capability over regular standard image. Mostly the standard image layer 3 switches can only handle static routing and basic layer 3 functionality. It totally depends on the switch though.

I don't have a 3550 in front of me, but I know with a 3560 you can turn a switchport into a layer 3 port with the "no switchport" command.

rolande
Certifiable
MVM,
join:2002-05-24
Dallas, TX
ARRIS BGW210-700
Cisco Meraki MR42

rolande

MVM,

Re: RE: can a l3 switch with full dynamic protocol

The 3550 works exactly the same way with just a different, "less capable" backplane architecture than the 3560. It can run with VLAN interfaces and route like a traditional Layer3 switch or you can use the no switchport command and turn a FastE interface into a Layer3 port. In that case, you can apply port ACLs directly to a layer3 port as well.

The 3550 can run pretty much any routing protocol. The only one I think not supported is IS-IS. Other than that it has a fairly full blown IOS implementation and can pretty much do most anything you would need.

tomatoe
Premium Member
join:2002-08-03
Kansas City, MO

tomatoe

Premium Member

said by rolande:

The 3550 can run pretty much any routing protocol. The only one I think not supported is IS-IS.
You thought right
ISIS can't be run on the 3550's, but you can on say, for example, the 3750's.

sporkme
drop the crantini and move it, sister
MVM
join:2000-07-01
Morristown, NJ

sporkme to belushi

MVM

to belushi

Re: RE: can a l3 switch with full dynamic protocol set

One thing I'm curious about in the L3 switch world... Back in the day there was a huge worm that had a side effect of rendering many "layer 3" switches useless. Once the worm hit, it tried to spread, and in the process of scanning for other hosts to infect it would flood these layer 3 switches' arp tables (pushing "good" entries, like upstream routers out of the forwarding table) and the switch would fall back to no longer doing flow-based forwarding, but per-packet forwarding.

Since many vendors at that point were playing up the flow-based PPS/Mb/s numbers and playing down the non-flow-based routing, lots of folks discovered that routers were best used in many cases.

Has this situation changed in the last few years?

rolande
Certifiable
MVM,
join:2002-05-24
Dallas, TX
ARRIS BGW210-700
Cisco Meraki MR42

rolande

MVM,

Re: RE: can a l3 switch with full dynamic protocol

Well you can always use NBAR to kill a good worm. But if you have a 6500 platform with an MSFC, the newer MSFC's are pretty much off-shoots of the 7200 NPE's. I believe the MSFC on a SUP720 is equivalent to an NPE-G1 which can put up some really hefty numbers. So they have a lot of horsepower and memory capability. On the smaller end, you can get burnt pretty badly in a situation like that because the processors are not scaled to handle process switching in the volumes you'd be seeing..