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layer 3 switch
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I believe that the main advantages other than modularity lie in the IOS versions that they are capable of using. The right router with an advanced enterprise featureset or certain security IOS's will have some capabilities that are not provided on the switch level yet. It would be easier to compare if you provide a specific router/switch ie. 2811 and 3560 so that we can make a comparison. If I were comparing I would check the IOS's for the two on the Cisco Feature Navigator
If both the switch and the router will perform the features that you want then I would probably opt in to the switch side for the improved performance due to ASICS processing (hardware as opposed to software)!
B Haines
CCNA R&S, ETA FOI
If both the switch and the router will perform the features that you want then I would probably opt in to the switch side for the improved performance due to ASICS processing (hardware as opposed to software)!
B Haines
CCNA R&S, ETA FOI
![[pipe]](/data/assets/smilies/pipe.gif "[pipe] [pipe]")
You guys are being awfully vague in your descriptions of layer 3 switches and their capibilities. I am going to have disagre with you Burt on your assumption that Layer 3 switches can't do most of the stuff that routers can do from a pure routing perspective because they sure can. Lets take for instance a 3560 or even a 3550 with updated software. These things can support pretty much the full range of EIGRP/RIP/OSPF/BGP/PIM/Static routing/etc. support with all the bells and whistles (yes -route maps too).
As for the routing of traffic between vlans, yes they can of course do that but ther ei sno reason that they can't be used to route between switches as well and are often used for these purposes.
I agree that if you want a router, buy a router, but today's switches are capable of so much (assuming you are running the right code) and a 3560 isn't even a top of the line switch.
As for the routing of traffic between vlans, yes they can of course do that but ther ei sno reason that they can't be used to route between switches as well and are often used for these purposes.
I agree that if you want a router, buy a router, but today's switches are capable of so much (assuming you are running the right code) and a 3560 isn't even a top of the line switch.
You're right...we really aren't answering the question. My thing is when I see L3 switch I don't think 3550 or 3560. I think 6500/4500.
As for advantages, I guess I have to give the typical Cisco answer of...it depends on what you are trying to do in order to see advantages one way or another. A router does give you some additional interfaces you can use for connectivity over 35x0 or a 4500 switch. The 6500 has a flexwan module that you can put what I guess I'd call more traditional router interfaces into. The flexwan will take the cards from a 7200 series router and will just be additional interfaces in the 6500.
With a router on a stick type of environment, you do have some limitations if you are using it to route between vlans. For instance, and to keep it simple, say you have a 2800 router connected to a 3550 switch and the router is trunked to the switch handling your inter-vlan routing. If you should happen to send a large image from one vlan to another, it has to cross the 100mbps uplink to the router and back down to get from point a to point b. This potentially could fill the link, and basically prevent other traffic from getting passed across the interface. A layer 3 switch would handle this in it's backplane.
I have not personally done a lot of routing with a 35x0 series. 6500..different story, so I can't really speak to how well the smaller switches perform with routing, but I can't imagine they add any delay. One thing I do know is that the 6500 with a flexwan module will not do traffic shaping. This is where my QoS remark comes in. Cisco explained to me that basically the 6500 is a switch first, router second. It will do policing, (which is more of a switching thing I think), than shaping.
As for advantages, I guess I have to give the typical Cisco answer of...it depends on what you are trying to do in order to see advantages one way or another. A router does give you some additional interfaces you can use for connectivity over 35x0 or a 4500 switch. The 6500 has a flexwan module that you can put what I guess I'd call more traditional router interfaces into. The flexwan will take the cards from a 7200 series router and will just be additional interfaces in the 6500.
With a router on a stick type of environment, you do have some limitations if you are using it to route between vlans. For instance, and to keep it simple, say you have a 2800 router connected to a 3550 switch and the router is trunked to the switch handling your inter-vlan routing. If you should happen to send a large image from one vlan to another, it has to cross the 100mbps uplink to the router and back down to get from point a to point b. This potentially could fill the link, and basically prevent other traffic from getting passed across the interface. A layer 3 switch would handle this in it's backplane.
I have not personally done a lot of routing with a 35x0 series. 6500..different story, so I can't really speak to how well the smaller switches perform with routing, but I can't imagine they add any delay. One thing I do know is that the 6500 with a flexwan module will not do traffic shaping. This is where my QoS remark comes in. Cisco explained to me that basically the 6500 is a switch first, router second. It will do policing, (which is more of a switching thing I think), than shaping.
The L3 switches I've been using have every router feature I've ever messed with: ACLs, RIP, OSPF, BGP, route-maps, traffic shaping, multicast routing (PIM-SM/SSM/DM, DVMRP), policy-based routing, etc.
The biggest difference I see with L3 vs routers is the interface choices.
MCSE CCNA CCDA
The biggest difference I see with L3 vs routers is the interface choices.
MCSE CCNA CCDA
dearingkr,
Once again I believe that examples would help.. Provide an example of the switch/router that you want to compare as well as the intended topology.. Lerdalt already covered switch advantages of the Router on a stick setup...
B Haines
CCNA R&S, ETA FOI
Once again I believe that examples would help.. Provide an example of the switch/router that you want to compare as well as the intended topology.. Lerdalt already covered switch advantages of the Router on a stick setup...
B Haines
CCNA R&S, ETA FOI
OK, the most recent example I can think of was when we upgraded our internet edge equipment.
Datacenter environment:
I have multiple high-bandwidth internet lines. One is gig fiber (100Mbps burstable) and a second is 100Mbps copper. I also needed failover and policy-based routing capability.
My first instinct was a beefy router. I looked at Cisco's 7000 series. It would do the job just fine and cost at least $30k each.
I ended up going with a Layer3 switch solution, Extreme Summit X450 for about $10k each.
In this case the choice was a no-brainer mainly because the type of interface was not an issue. The bonus was, it was significantly cheaper.
Note that the choice of Extreme over Cisco Layer3 switches was mainly due to the fact that all other existing switching is Extreme.
p.s. I know this is a Cisco forum, but I assume the original question refers to Layer3 switches in general.
MCSE CCNA CCDA
Datacenter environment:
I have multiple high-bandwidth internet lines. One is gig fiber (100Mbps burstable) and a second is 100Mbps copper. I also needed failover and policy-based routing capability.
My first instinct was a beefy router. I looked at Cisco's 7000 series. It would do the job just fine and cost at least $30k each.
I ended up going with a Layer3 switch solution, Extreme Summit X450 for about $10k each.
In this case the choice was a no-brainer mainly because the type of interface was not an issue. The bonus was, it was significantly cheaper.
Note that the choice of Extreme over Cisco Layer3 switches was mainly due to the fact that all other existing switching is Extreme.
p.s. I know this is a Cisco forum, but I assume the original question refers to Layer3 switches in general.
MCSE CCNA CCDA
This switch is listed as a CE/PE Edge switch (among other topologies)... The only things that really seem to jump out (don't seem to be an issue for you) is the fact that you are limited to 802.1X/RADIUS for AAA as opposed to TACACS+ or a hybrid Kerberos/TAC+ design.. The switch supports RIP/OSPF.. I personally love EIGRP but I think you said that you were already running OSPF so good to go there..
I would still couple this switch with a CISCO IDS/IPS or another IDS/IPS sytem.. I know that this has a zero day threat system but two vendors are ALWAYS better than one. Your Extreme switch (and hopefully the rest) support SNMPv3 and so will the IDS/IPS so you will have a nice immediate threat notification system if you choose to. I like the defense-in-depth features of this switch.
All in all I believe that for the most part you are right in your initial assessment.. mainly just the lack of modules which does not seem to both you.
Finally, I will say this.. I have very little experience with Extreme other than the two I bought from a guy on eBay... This guy is a CCVP that maintains the network for a law firm and he basically warned me when I bought the two L3 switches that in his opinion Extreme was junk! That is a quote.. I have read both sides of this online with many posts in regard to extreme ports going bad etc. I have also had a few people tell me that they loved Extreme and have had a great experience so I really can't say.. All I know is that this guy was selling a product and warned me ahead of time, in all earnest, that he had been using these switches for over a year and was replacing all Extreme Network Summit switches with Cisco switches and the law firm had approved it... There is an old saying.. you get what you pay for but hopefully you will be one of those people that experience no problems and have a good experience.. Wish you the best of luck!
B Haines
CCNA R&S, ETA FOI
I would still couple this switch with a CISCO IDS/IPS or another IDS/IPS sytem.. I know that this has a zero day threat system but two vendors are ALWAYS better than one. Your Extreme switch (and hopefully the rest) support SNMPv3 and so will the IDS/IPS so you will have a nice immediate threat notification system if you choose to. I like the defense-in-depth features of this switch.
All in all I believe that for the most part you are right in your initial assessment.. mainly just the lack of modules which does not seem to both you.
Finally, I will say this.. I have very little experience with Extreme other than the two I bought from a guy on eBay... This guy is a CCVP that maintains the network for a law firm and he basically warned me when I bought the two L3 switches that in his opinion Extreme was junk! That is a quote.. I have read both sides of this online with many posts in regard to extreme ports going bad etc. I have also had a few people tell me that they loved Extreme and have had a great experience so I really can't say.. All I know is that this guy was selling a product and warned me ahead of time, in all earnest, that he had been using these switches for over a year and was replacing all Extreme Network Summit switches with Cisco switches and the law firm had approved it... There is an old saying.. you get what you pay for but hopefully you will be one of those people that experience no problems and have a good experience.. Wish you the best of luck!
B Haines
CCNA R&S, ETA FOI
Yes, I really do miss the simplicity of EIGRP, but of course that is proprietary to Cisco. So I have to 'make do' with OSPF.
As far as reliability, I've only RMA'd 1 in 3 years (I've got about 50 switches), so it seems comparable to Cisco so far.
The cost is about 10-20% less than a comparable Cisco.
The CLI is an entirely different animal, took some time to learn. What also is a pain is that there are 2 OS's to learn.
MCSE CCNA CCDA
As far as reliability, I've only RMA'd 1 in 3 years (I've got about 50 switches), so it seems comparable to Cisco so far.
The cost is about 10-20% less than a comparable Cisco.
The CLI is an entirely different animal, took some time to learn. What also is a pain is that there are 2 OS's to learn.
MCSE CCNA CCDA
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