Tag Archives: CiscoNexus

L3 vPC Support on Nexus 5k

So… I’m a little embarrased to admit this but I only very recently found out that there are significant differences in how Virtual Port Channels (vPC) behave on the Nexus 5k vs the Nexus 7k when it comes to forming routing adjacencies over the vPC.

Take the title literally!
Take the title literally!

I’ve read the vPC Best Practice whitepaper and have often referred
others to it and also referred back to it myself from time to time. What I failed to realize is that I should’ve been taking the title of this paper more literally: it is 100% specific to the Nexus 7k. The behaviors the paper describes, particularly around the data plane loop prevention protections for packets crossing the vPC peer-link, are specific to the n7k and are not necessarily repeated on the n5k.

Continue reading L3 vPC Support on Nexus 5k

NSF and GR on Nexus 5000

NSF and GR are two features in Layer 3 network elements (NEs) that allows two adjacent elements to work together when one of them undergoes a control plane switchover or control plane restart.

The benefit is that when a control plane switchover/restart occurs, the impact to network traffic is kept to a minimum and in most cases, to zero.

Continue reading NSF and GR on Nexus 5000

Random Notes From My Third CPOC

I was lucky enough (volunteering for very challenging work is luck, right? 😁) to finish my third tour through Cisco CPOC last wcpoceek. CPOC is Cisco’s Customer Proof of Concept facility where customer’s can bring their network design, build it in Cisco’s lab, and beat the hell out of it. CPOC has tons of network and compute gear, all the right testing tools and processes, and excellent work areas that cater to collaborative work and information sharing. It’s also staffed by very senior and experienced engineers.

I know it’s cliche and I know I’m biased because I have an @cisco.com email address, but I’ve truthfully never seen anything like CPOC before. And the customer’s I’ve worked with at CPOC haven’t either. It’s extremely gratifying to take something you built “on paper” and prove that it works; to take it to the next level and work those final kinks out that the paper design just didn’t account for.

If you want more information about CPOC, get in touch with me or leave a comment below. Or ask your Cisco SE (and if they don’t know, have them get in touch with me).

Anyways, on to the point of this post. When I was building the topology for the customer, I kept notes about random things I ran into that I wanted to remember later or those “oh duh!” moments that I probably should’ve known the answer to but had forgotten or overlooked at the time. This post is just a tidy-up of those notes, in no particular order.

Continue reading Random Notes From My Third CPOC

Avoiding an ISSUe on the Nexus 5000

The idea for this post came from someone I was working with recently. Thanks Fan (and Carson, and Shree) :-)

In Service Software Upgrade (ISSU) is a method of upgrading software on a switch without interrupting the flow of traffic through the switch. The conditions for successfully completing an ISSU are usually pretty strict and if you don’t comply, the hitless upgrade can all of a sudden become impacting.

The conditions for ISSU on the Nexus 5000 are pretty well documented (cisco.com link) however, there are a couple bits of knowledge that are not.  This post is a reminder of the ISSU conditions you need to comply with and a call out to the bits of information that aren’t so well documented.

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Speaking Notes: The Data Center Network Evolution

I will be presenting at the Cisco Connect Canada tour in Edmonton and Calgary on November 3rd and 5th, respectively. My presentation is about that three letter acronym that everyone loves to hate: SDN :-)

I will talk about SDN in general terms and describe what it really means; what we’re really doing in the network when we say that it’s “software defined”. No unicorns or fairy tales here, just engineering.

Next I’ll talk about three areas where Cisco is introducing programmability into its data center solutions:

  • Application Centric Infrastructure
  • Virtual Topology System
  • Open NX-OS

Below are the notes I made for myself while researching these topics and preparing for the presentation. At the bottom of this post is a Q&A section with some frequently asked questions.

Continue reading Speaking Notes: The Data Center Network Evolution

IOS and NX-OS Platform Identifiers

I was preparing a presentation the other day about the high level differences between IOS, IOS-XE and NX-OS and one of the things I included in the presentation was the various platform and branch identifiers that’s used in each OS. It’s just a bit of trivia that I thought would be interesting and might come in handy one day. I’m posting the information I collected below so everyone can reference it.

Continue reading IOS and NX-OS Platform Identifiers

Five Functional Facts about OTV

Following on from my previous “triple-F” article (Five Functional Facts about FabricPath), I thought I would apply the same concept to the topic of Overlay Transport Virtualization (OTV). This post will not describe much of the foundational concepts of OTV, but will dive right into how it actually functions in practice. A reasonable introduction to OTV can be found in my series on Data Center Interconnects.

So without any more preamble, here are five functional facts about OTV.

Continue reading Five Functional Facts about OTV

An Introduction to the Nexus 7700

We’re halfway through 2013 and we have our second new member of the Nexus family of switches for the year: the Nexus 7700. Here are the highlights:

  • Modular, chassis-based system
    • 18 slot (16 IO modules) and 10 slot (8 IO modules)
  • True front-to-back airflow
  • New fabric modules
    • (6) fabric modules (maximum) per chassis
    • 220G per slot per fabric module
    • 1.32Tbps per IO module slot
  • Supports F2E and newly announced F3 IO modules Continue reading An Introduction to the Nexus 7700

Nexus 7000 IO Module SKU Cheat Sheet

Wow the title of this post is a mouthful.

Similar to my previous post on the Nexus 2000 (Nexus 2000 Model Number Cheat Sheet), this post will explain what the letters and numbers mean in the Nexus 7000 IO module part numbers. This will allow you to quickly identify the characteristics of the card just by looking at the part number which in turn should help you out as you’re building BOMs and picking the right card for the job.

Update July 2, 2013: Updated to reflect release of the Nexus 7700 and F3 modules.

Continue reading Nexus 7000 IO Module SKU Cheat Sheet

An Introduction to the Nexus 6000

There’s a new Nexus in the family, the Nexus 6000. Here are the highlights.

Nexus 6001 Nexus 6004
Size 1 RU 4 RU
Ports 48 x 10G + 4 x 40G 48 x 40G fixed + 48 x 40G expansion
Interface type SFP+ / QSFP+ QSFP+
Performance Line rate Layer 2 and Layer 3
Latency 1μs port to port
Scalability 128K MAC + 128K ARP/ND (flexible config), 32K route table, 1024-way ECMP, 31 SPAN sessions
Features L2/L3, vPC, FabricPath/TRILL, Adapter FEX, VM-FEX
Storage FCoE
Visibility Sampled Netflow, buffer monitoring, latency monitoring, microburst monitoring, SPAN on drop/high latency

Continue reading An Introduction to the Nexus 6000