Friday 7 March 2014

Introduction to VDC and vPC

So I've decided to start reading an NX-OS book (http://www.amazon.com/NX-OS-Cisco-Nexus-Switching-Next-Generation/dp/1587143046). Considering the company I work for intends to overhaul our data centre, I thought it would be a great idea to start reading some of this stuff.

I am following CCIE Data Centre book recommendation list, which means a long list of books that need to be covered. Started this book two days ago, and though I am uncertain that I'll ever pursue CCIE DC, I am excited to go through new technologies I am not familiar with. 

Since I am not feeling well today, I couldn't even get my eyes to read 3 pages of vPC, I'd like to gather my thoughts on what I read so far, also as a summary so I can quickly glance through my own post if I need to check something.

NX-OS is not so different than IOS in terms of networking technologies. Most of it are still the same (with the exception of syntax, of course). STP is still the same ol' STP, private VLAN, VTP, LACP, Etherchannel (or new fancy name Port channel) have the same concept with IOS.

Difference in technology comes with VDC and vPC (so far about 15% completed on the book).

VDC allows us to have multiple virtual switch inside one physical switch and those VDCs are isolated one another. 

vPC is a virtual port channel which allows us to share a port channel between two different NX-OS devices. It relies on these two configuration:

1. vPC keepalive, which basically is assigning an IP address to and interface (for each NX-OS devices participating in vpc), put it in vrf member vpc-keepalive and ensure they can ping each other. In short, it's a Layer 3 heartbeat link.

Messages are UDP port 3200, with 96 bytes long (32 bytes of it are payload).

2. vPC peer-link, in easier sentence to understand (at least for me), is to tell an NX-OS device who is it's neighbor. This is used to exchange state information between vPC peers.

vPC peer-link is a Layer 2 trunk acts to sync MAC Address, vPC state, CFS (Cisco Fabric Service), IGMP, etc. 

Minimum connection is 10G Ethernet.

Steps to configure vPC:

1. Enable feature vpc
2. Create a vrf context [keepalive-test]
3. Assign IP address to an interface on each NX-OS device
4. Assign the created vrf to this interface on each NX-OS device
5. Ensure the NX-OS devices can ping each other
6. Configure peer-keepalive destination [peer keepalive IP address] source [own keepalive IP address] vrf [keepalive-test]. This is configured in vpc domain level.
7. Configure vpc peer-link in the port channel between NX-OS devices
8. Add port channels to the vPC.



Next I would read about vpc peer-gateway, vpc peer-switch and FabricPath.

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