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Nexus Product Line (High-Level)

January 1, 2014

Cisco has a few switches in the Nexus family. I can’t say how deep CCNA Data Center goes into the product line[1] but it’s worth covering anyways.

Nexus 7000

The flagship of Cisco’s product line is the Nexus 7000 series[2]. These are chassis switches in four physical form factors:

  • 7004 – 4 slot
  • 7009 – 9 slot
  • 7010 – 10 slot
  • 7018 – 18 slot

Each chassis has two slots available for supervisors. Neither slot is capable of running IO line cards as they are dedicated to the supervisor.

There are a few components inside the Nexus 7000.

Supervisor

The supervisor is responsible for management of the device as well as control plane processes. In many ways it is similar to a supervisor in a 4500 or 6500 except it is not responsible for data plane traffic. Nexus 7000 has three supervisor options: Sup1, Sup2, and Sup2E. Cisco offers a nice comparison of the differences on their website so I’d rather not re-iterate here. In sum, the differences are

  • Amount of memory available
  • FCoE capabilities
  • VDC capabilities
  • FEX capacity

Fabric

Nexus 7000 enjoys scalability because of its fabric modules. The fabric connects the line cards together and transports traffic from line card to line card. Fab–1 and Fab–2 modules are available providing 46 and 110Gbps per slot per fabric module respectively. This means if a 7010 has 3 line cards in it, each line card will have 110Gbps of backplane connectivity per Fab–2 installed. Nexus 7004 does not use fabric modules as the concept is embedded in the chassis.

Line Cards

Line cards are what provides the physical ports. When designing a Nexus 7000 solution, this is where mistakes are made. Four types of line cards are available:

  • M1
  • F1
  • F2
  • F2E

M1

The M1 was the original line card with tons of TCAM memory and ASICs. They support OTV, MPLS, and license enabled expanded memory[3]. However, other advanced features such as FCoE and FabricPath are not available on the M-series.

M2 line cards are available but are probably newer than what is on the test. See the Nexus 7000 data sheets for more information.

F1

F1 was released as a less expensive line card but with FCoE and FabricPath support. Latency is lower as is price. However, these rely on an M1 for traffic forwarding[4]. In other words, if an F1 card must send traffic to another F1 card, the traffic needs to go through an M1 first. If a F1 line card lacks a M1 card to bind to, it is able to forward traffic but only at layer 2.

F2

F2 line cards were designed so they are not able to be in the same VDC as a M1 line card[5]. I am not aware of the rationale behind it but this caused some heartache during design phases.

F2E

F2E line cards were released to fix the compatibility problems with the F2. They support FCoE and FabricPath but still do not support OTV or MPLS which is still the responsibility of the M1 series. These are the default line cards I used for traffic in my designs unless an M-series is required.

Nexus 6000

The Nexus 6000 series is optimized for 10 and 40Gbps traffic. The 6001 offers 48 ports of 1 or 10Gbps SFP/SFP+ ports whereas the 6004 is more of a chassis covering up to 96 40Gbps ports. 6001 also has 4 40Gbps uplink ports. Any 40Gbps port on the 6000 series is capable of using quad-breakout cables effectively creating 4 10Gbps connections.

FabricPath and FCoE are both supports on all Nexus 6000 switches. Additionally, it offers line rate layer 2 and layer 3 throughput.

Nexus 5000

If there’s one switch which was almost good enough but still has a unique place in the product line, despite its deficiencies, it is the Nexus 5000. Its uniqueness is because it supports native FibreChannel. Each port on the 5500UP series can be configured using 1/10Gbps Ethernet SFPs or FC SFPs. Be wary of the ordering of the ports but the different protocols can be used on the same switch simultaneously. Very cool.

Unfortunately, layer 3 support is provided by an additional module or daughter card operating at 160Gbps. All traffic, management or otherwise, needs to go through this module. If this module is saturated, there is possibility for traffic to be dropped, corrupted, or the administrator may not be able to access the management console to solve the problem. I like the 5000 for FC or layer 2 connectivity but steer toward Nexus 6000 if layer 3 is a requirement.

Nexus 3000

Of all the physical Nexus switches, I have the least design experience with the 3000 series. They’re low-latency, high-performance switches marketed toward financial services or big data firms. However, they can be nice top of rack switches as well.

Nexus 2000

Here is where Cisco got creative. Nexus 2000 isn’t really a switch at all. Instead it’s more of a remote line card. It doesn’t have much intelligence on board, just enough to do the bare minimum. Instead, all forwarding decisions are made on the upstream Nexus 5000, 6000, or 7000 switch thanks to 802.1BR. Nexus 2000 offers a very nice top of rack “switch” at a low price point. Management is also great since it appears as a line card on the parent switch.

Future posts will go into 802.1BR and uplinking methods of the Nexus 2000 family.

Nexus 1000V

1000V stands alone as it is a hypervisor based switch, replacing the vSwitch in VMware ESXi. Network administrators can now use their Nexus skills to administer hypervisor switches. A future post will go into the architecture of the 1000V.

Summary

Cisco’s Nexus product line has matured quite a bit over the years. Future posts will go into detail about each one. For now, this will get you started on the Nexus product line.


  1. I haven’t taken the test and people aren’t allowed to talk about test contents anyways.  ↩
  2. Ignore the 7700 and recently announced 9000 for the sake of this discussion.  ↩
  3. Expanded memory only certain models.  ↩
  4. http://www.cisco.com/en/US/docs/solutions/Enterprise/Data_Center/VMDC/2.6/vmdcm1f1wp.html  ↩
  5. https://supportforums.cisco.com/thread/2211563  ↩
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