Re: Any 1U - 2U Ethernet switches that can handle 4K VLANs?
On Sun, 25 Jan 2004, Bill Nash wrote:
On Sun, 25 Jan 2004, ken emery wrote:
The point of using VLANs is that you don't need to route. There's probably a good reason for switching instead of routing in the original poster's scenario. (Perhaps a FTTH-like project?)
Correct me if I'm wrong here, but at some point you will have to route all those VLAN's. To really answer the question about wether > 1000 VLAN's are necessary one would need to see the network design.
I would argue this point. I've got a production environment sporting multiple vlans, none which will ever see an external subnet or even a gateway (think databases.) The operative context inherent in the VLAN acronym is, after all, 'local', and not every topology requires routing.
This is correct, but then why spend the money on a L3 switch? Routing isn't needed so save the money and purchase a L2 switch. bye, ken emery
L3 switchiong is just term for idiots - it is ROUTING in old terms. So, VLAN's means _routing_. The point of using VLAN's is that, in many cases, IP routing for VLANs is provided by the switching fabric, very effectively. And that you have universal patching - everything is very flexible. But .. managing 100 Cisco 3550 (or other venor, no matter) switches wiith 4,000 VLAN's... brr, it is a very seriuos task. I'd think about central 6509 switch(es), with a few local (in rack) dumb 3524 switches to decrease a patching... or about private VLAN (single!) . If they mean dynamic VLAN's so that they assign VLAN to the MAC, they expect to assign 4,000 different VLAN's. Having 4,000 LVALs means that workstations are just isolated. Ok, set up 1 (one) private VLAN, and workstations are isolated (be very careful, because it will require careful ARP configuration, careful proxy arp etc etc... but it is possible. Or just keep 1 VLAN and many ssecondary IP per interface... I think, that you can find many options.). May be (I can not exclude it), they have a very good idea, which pay off when configured. As I was saying, I can not exlude it, and I am sure, that it is possible to find non-cisco L3 switches, able to do such task much better than Cisco. The only drawback is _time te test it all_ and _time to select such vendor_. ----- Original Message ----- From: "ken emery" <ken@cnet.com> To: <nanog@merit.edu> Sent: Sunday, January 25, 2004 5:18 PM Subject: Re: Any 1U - 2U Ethernet switches that can handle 4K VLANs?
On Sun, 25 Jan 2004, Bill Nash wrote:
On Sun, 25 Jan 2004, ken emery wrote:
The point of using VLANs is that you don't need to route. There's probably a good reason for switching instead of routing in the
original
poster's scenario. (Perhaps a FTTH-like project?)
Correct me if I'm wrong here, but at some point you will have to route all those VLAN's. To really answer the question about wether > 1000 VLAN's are necessary one would need to see the network design.
I would argue this point. I've got a production environment sporting multiple vlans, none which will ever see an external subnet or even a gateway (think databases.) The operative context inherent in the VLAN acronym is, after all, 'local', and not every topology requires routing.
This is correct, but then why spend the money on a L3 switch? Routing isn't needed so save the money and purchase a L2 switch.
bye, ken emery
On Sun, 25 Jan 2004, Alexei Roudnev wrote: : :L3 switchiong is just term for idiots - it is ROUTING in old terms. So, :VLAN's means _routing_. Um, no, VLAN does not infer routing. 802.1q and even Cisco's ugly proprietary ISL both operate at layer two. As to "L3 switching" and the spin involved in such, it's an old, predictable story, which we all wrote off as marketing drivel at least a couple years ago...
1) Cisco ISL is much better than urgly 802.1q - first of all, it was designed many years before 802.1q. I am not even talking abiout those idiots, who designed 802.1q as a _spanning tree on the trunk level_, which made many configurations (which we used with ISL ain 199x years) impossble, and caused vendors to extend 802.1q. 2) Of course, VLAN does not infer routing. But VLAN routing can be provided on the switch fabric, effectively bypassing many traditional drawbacks - see Cisco 6509, for example. ----- Original Message ----- From: "Brian Wallingford" <brian@meganet.net> To: "Alexei Roudnev" <alex@relcom.net> Cc: "ken emery" <ken@cnet.com>; <nanog@merit.edu> Sent: Sunday, January 25, 2004 10:17 PM Subject: Re: Any 1U - 2U Ethernet switches that can handle 4K VLANs?
On Sun, 25 Jan 2004, Alexei Roudnev wrote:
: :L3 switchiong is just term for idiots - it is ROUTING in old terms. So, :VLAN's means _routing_.
Um, no, VLAN does not infer routing. 802.1q and even Cisco's ugly proprietary ISL both operate at layer two.
As to "L3 switching" and the spin involved in such, it's an old, predictable story, which we all wrote off as marketing drivel at least a couple years ago...
On Jan 26, 2004, at 2:04 AM, Alexei Roudnev wrote:
1) Cisco ISL is much better than urgly 802.1q - first of all, it was designed many years before 802.1q. I am not even talking abiout those idiots, who designed 802.1q as a _spanning tree on the trunk level_, which made many configurations (which we used with ISL ain 199x years) impossble, and caused vendors to extend 802.1q.
Is it April 1st? ISL changes the size of packets, does it not? So know you have to deal with MTU issues. What happens when I want the biggest MTU possible? I know it is not much a difference in size, but for some people, size does matter. I am quite happy with dot1q. My gripe is with poor spanning-tree implementations. I don't want a single spanning-tree for every vlan on a trunk... I like standards, but I am happy with Rapid-PVST. Just my feelings about the issue. I would never deploy ISL unless I had something like a 1900 that did not do dot1q
2) Of course, VLAN does not infer routing. But VLAN routing can be provided on the switch fabric, effectively bypassing many traditional drawbacks - see Cisco 6509, for example.
Are you talking about multilayer switching implementations? That is why C came out with dCEF. I costs, but if you want to do serious routing, damn if it ain't fast ;-)
----- Original Message ----- From: "Brian Wallingford" <brian@meganet.net> To: "Alexei Roudnev" <alex@relcom.net> Cc: "ken emery" <ken@cnet.com>; <nanog@merit.edu> Sent: Sunday, January 25, 2004 10:17 PM Subject: Re: Any 1U - 2U Ethernet switches that can handle 4K VLANs?
On Sun, 25 Jan 2004, Alexei Roudnev wrote:
: :L3 switchiong is just term for idiots - it is ROUTING in old terms. So, :VLAN's means _routing_.
Um, no, VLAN does not infer routing. 802.1q and even Cisco's ugly proprietary ISL both operate at layer two.
As to "L3 switching" and the spin involved in such, it's an old, predictable story, which we all wrote off as marketing drivel at least a couple years ago...
ISL _DOES NOT CHANGE_ packet size.
Is it April 1st? ISL changes the size of packets, does it not? So know you have to deal with MTU issues. What happens when I want the biggest MTU possible? I know it is not much a difference in size, but for some people, size does matter.
I am quite happy with dot1q. My gripe is with poor spanning-tree
2) Of course, VLAN does not infer routing. But VLAN routing can be provided on the switch fabric, effectively bypassing many traditional drawbacks - see Cisco 6509, for example.
Are you talking about multilayer switching implementations? That is why C came out with dCEF. I costs, but if you want to do serious routing, damn if it ain't fast ;-) Agree in general.
participants (4)
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Alexei Roudnev -
Brian Wallingford -
ken emery -
Peter J Hill