Cisco Routed Ports on Layer 3 Switch

Yeah, some do it, some don't. I typically still like an actual router on the front end
 
More features, more processing ability. A router is preferred but a switch can perform light duty.
 
L3 switches tend to have significantly more processing power... Your router has, what, 2 ports? The switch still has to run L3 features on all 24, 48, or however many ports.
 
Right, but it seems like he's talking about the router having more processing ability (he has that along with more features, which is true of the router, not the switch), which is not true.
 
A proper router will have a lot more L3 functionality and performance compared to an L3 switch. You must be thinking of your cable/dsl/fios router, which is a toy compared to a real router.

L3 switches can range from bare nothing to damn near full routers, capabilities and horsepower vary widely.

However if you are just doing static routes, pbr, or rip, l3 switches can be quite doable.
 
uunut said:
A proper router will have a lot more L3 functionality and performance compared to an L3 switch.
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More functionality: Yes (which I've already posted)
More performance: No

Routers route in software, L3 switches route in ASICs. ASICs are much, much faster. The highest end routers have ASICs as well, but your average Cisco router is software based and throughput is much lower than even a slow L3 switch
 
Layer3 switches generally can't take WAN ports (CSU/DSU, T1s, T3s, etc), while a router can.
 
You'll find that "routers" really only exist for WAN connectivity these days. For internal routing it's pretty much L3 switches. And yes, L3 switches can be VERY fast.
 
Vito_Corleone said:
Right, but it seems like he's talking about the router having more processing ability (he has that along with more features, which is true of the router, not the switch), which is not true.
Click to expand...

Right, I wasn't going against what you said; more of a response to the post above yours, or complementing your post with some info.
 
NetJunkie said:
You'll find that "routers" really only exist for WAN connectivity these days. For internal routing it's pretty much L3 switches. And yes, L3 switches can be VERY fast.
Click to expand...

This is what I do as a standard, depending on the hardware in my locations.

If I have a 3560G switch and a 2811 router in a small location, I make the 3560 be the default-gateway for the PC's and the WAN router is just another node off the switch - which takes them to our MPLS cloud. Both devices share the routing table. This way I can get a 100Mb router like the lowly 2811 and it's more than sufficient. It's also easy to swap out the router without affecting internal traffic or redirect them to a firewall for a backup VPN in case the 2811 dies.
 
Protoform-X said:
L3 switches tend to have significantly more processing power... Your router has, what, 2 ports? The switch still has to run L3 features on all 24, 48, or however many ports.
Click to expand...

Sort of ... I think we're on the same page.

The ASICs in a L3 switch can do some functions in their sleep across all the ports. Pretty much all the 10gig/40gig 1U switches can do line-rate routing between vlans if all the ports were 100% utilized.

But for the functions it can't do in the port ASICs, it has significantly less processing power (IMO, the first gen 3750 is awful in this regard). And most advanced routing features aren't even available on L3 switches.

Then it gets more confusing when you look at the feature rich supervisor 720 or 2T ... is it more of a router or a switch? I use them extensively for both purposes in my organization.
 
Most good L3 switches will talk BGP/OSPF/EIGRP no problem. I meant more at the IP services level.

No NAT support
No GRE support
No per-packet load balancing
No MPLS
Weaker traffic accounting (no netflow, less working counters)
Weaker QoS policies (no NBAR, no MQC, no object-groups, no egress policing, less complexity allowed in policies)
Weaker WCCP support (only cisco switch that will accept an extended redirect ACL is a 6500)
Weaker PBR support
Much smaller route memory

sup720 supports all of the above except per-packet balancing ... which is why it's hard to call it a router or a switch.
 
Ah, ok. I agree on everything but Netflow, GRE and WCCP. Netflow is supposedly available on the lower end Cisco gear now. GRE is supported on the lower end Cisco L3 stuff, but it runs in software. And Cat 3k stuff can take extended ACLs for WCCP, but not denies within the ACL.

Encryption is another big thing L3 switches tend to lack.
 
Is GRE supported on the 3750 in newer code now? I had to build a tunnel to some stupid vendor on a 4948 because it wasn't. And netflow wasn't working on it either ... but maybe the new gen 3750 does it? I don't buy them anymore.

WCCP doesn't support an extended ACL on a 3K or even a 4K. It supports an "expanded" ACL, which is nothing more but to allow more standard ACL numbers. Believe me, I learned this the hard way on a 4900M a month ago.
 
According to my experience, and this cheat sheet from Cisco, you're wrong about WCCP.

Platform-Recs-1.jpg


Again, 3750s will take extended ACLs (L4 info), but will not allow denies. 4500s don't even have the option for a redirect list in IOS. That was a fun discovery before I came across this sheet, lol.

As for GRE, somewhere in my head I remember terminating a tunnel to a 3750 in production. I also just tested it on a 3750-24T (122-55.SE) and 2811 at home. AFAIK, it's all in software though.
 
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