Catalyst 6500: The End Isn't Nigh...

Since Cisco launched the new Nexus range of switches, quite a number of people have asked me whether the advent of the Nexus switches heralds the demise of the Catalyst 6500. Furthermore, I have heard that some of Cisco's competitors have been telling anyone who will listen that the 6500 will soon be gone.

Anyway, with all this apparent uncertainty (or misinformation) around I thought I'd find out what is really going on, so I asked some folks at Cisco and they confirmed that the 6500 will be around for a long time to come.

Apparently, the 6500 has a development roadmap until at least 2012, and even if development of the 6500 comes to an end in 2012, it will still be another five years or so after that until Cisco stops support.

Actually, if you compare (and contrast!) the 6500 and Nexus platforms, you can see that they are complementary. Here are some of the major differences:

• The 6500 is optimized for 1Gbps, supports 10Gbps, and will support 40Gbps in future.
• The Nexus supports up to 10 Gbps today, and will support both 40 Gbps and 100 Gbps (802.3ba) in future.
• The 6500 will support up to 80Gbps per slot, while the Nexus will support up to 500 Gbps per slot.
• Both the 6500 and Nexus support virtualization, but in different ways - the 6500 supports virtualization of multiple chassis with the Virtual Switching System (VSS) 1440, while the Nexus supports virtualization within a single chassis with Virtual Device Contexts (VDCs).
• The Nexus will support the unification/convergence of Ethernet and storage (Fibrechannel over Ethernet [FCoE]) networks - something the 6500 is not capable of doing.
• Software processes are completely modularized on the Nexus, while they can only be partially modularized on the 6500.
• The 6500 supports both the older 802.1D standard (that's slooooooooow Spanning Tree Protocol), as well as the much faster 802.1w, while the Nexus supports 802.1w. I assume Nexus includes per port backward compatibility with 802.1D per the 802.1w standard, but I haven't had time to confirm that.
• The 6500 supports PagP and LACP (802.3ad) with Etherchannel, while the Nexus supports only LACP.
• The 6500 supports Layer-4 to 7 services such as firewalling and content switching. The Nexus does not support those kinds of services.
• The 6500 supports VTP, while the Nexus doesn't (hooray!).
• The 6500 supports legacy protocols such as IPX, but the Nexus doesn't.
• The 6500 supports MPLS, while the Nexus doesn't.

In summary, there are some things that the Nexus can do that the 6500 can't (convergence of Ethernet and storage networks, and so on), and there are a limited number of things that the 6500 can do that the Nexus can't (legacy protocol support, L4-L7 services).

Over the coming years, I expect to see the Nexus appearing in the core of high performance, converged networks, while the 6500 is used more and more at the distribution and access layers and for specialized tasks such as providing L4-L7 services, WAN connectivity, and carrier Ethernet (EoMPLS). But, it seems that it will be a very long time before the 6500 disappears altogether from our networks.

Mark