paulo999
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Layer 2 WAN link vs Layer 3 WAN
Hi, the company where I work has a combination of layer 2 WAN links and layer 3 WAN links.
Could someone please explain the difference between the two, and in what circumstances you would use each type?
Does layer 2 means the links are switched with MAC addresses and layer 3 is routed via IP addresses?
Thanks
Could someone please explain the difference between the two, and in what circumstances you would use each type?
Does layer 2 means the links are switched with MAC addresses and layer 3 is routed via IP addresses?
Thanks
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Thanks very much for the info.
I need to put a plan together for a smaller network for about 250 users and about 3 ESXi hosts, with Avaya VoIP. I was planning on using a Cisco 4500 for the core with Cisco 2960S as the access. To save costs it has been suggested to use 2x3750s for the core switches. Normally I would stack the two 3750s together to effectively make them act as one switch, but it’s been suggested that the two 3750s should have layer 3 link between them, but I don’t really understand why. Would it be because you can then do QoS etc between the two switches? Would that make the two 3750s on different subnets/VLANS?
For my own knowledge; Is the reason for using layer 3 instead of layer 2 between switches in this manner so you have features like QoS? I think I’ve read that you should do layer 3 between core switches, and distribution switches to core switches. So would each level of switch effectively be on its own subnet/VLAN?
Sorry if this is a dumb question :-)
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ASKER
Excellent, thank you.
One last thing I don’t quite understand fully – if you had, say, 2x3750s as your core, why would you put a layer 3 link between them both and not just put them both together in a stack?
Surely the bandwidth between the two switches in a stack is significantly more than just trunking two 1Gb ports together?
One last thing I don’t quite understand fully – if you had, say, 2x3750s as your core, why would you put a layer 3 link between them both and not just put them both together in a stack?
Surely the bandwidth between the two switches in a stack is significantly more than just trunking two 1Gb ports together?
ASKER
Thanks for all comments
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Layer-2 means basically that the frames are being switched based on MAC addresses rather than IP addresses in the packets for layer-3 services.
The infrastructure over which these services run can rely on a broad range of technologies, either layer-2, layer-2.5 (MPLS) or pure layer-3 or sometimes SONET/SDH for unoversubscribed layer-2 services.
Depending on the services you're planning to use over the network, oversubscription and QoS requirements, you might prefer a carrier over the other depending on their backbone and service design.
Be mindful also that layer-3 services comes with more intelligent service portals from the carriers cause they have higher visibility into the network...
HTH,