Tuesday 19 May 2015

IOS to NX-OS reference

We're in the process of setting up our Nexus 7010s to replace our Catalyst 6509Es as our data centre routers.  This configuration requires that we port our IOS distribution router configuration to NX-OS.

It's quite easy to find these using Google, but I've found these Cisco docwiki references helpful:

Basic IPv4 BGP comparison

As a taster, here is part of our BGP configuration for a distribution router in IOS:

router bgp 64602
 bgp router-id 192.84.5.248
 no bgp default ipv4-unicast
 bgp log-neighbor-changes
 !
 neighbor core_peers peer-group
 neighbor core_peers remote-as 64602
 neighbor core_peers update-source Loopback0
 neighbor core_peers timers 10 35
 !
 neighbor 192.84.5.240 peer-group core_peers
 neighbor 192.84.5.250 peer-group core_peers
 !
 address-family ipv4
  neighbor core_peers send-community
  neighbor core_peers soft-reconfiguration inbound
  neighbor 192.84.5.240 activate
  neighbor 192.84.5.250 activate
  maximum-paths 2
  maximum-paths ibgp 2
  no auto-summary
  no synchronization
 exit-address-family
 !
 address-family ipv4 multicast
  neighbor core_peers send-community
  neighbor core_peers soft-reconfiguration inbound
  neighbor 192.84.5.240 activate
  neighbor 192.84.5.250 activate
 exit-address-family

... and here's the equivalent in NX-OS:

router bgp 64602
  router-id 192.84.5.248
  log-neighbor-changes
  !
  address-family ipv4 unicast
    maximum-paths 2
    maximum-paths ibgp 2
  !
  address-family ipv4 multicast
    maximum-paths 2
    maximum-paths ibgp 2
  !
  template peer core_peers
    remote-as 64602
    update-source loopback0
    timers 10 35
    address-family ipv4 multicast
      send-community
      soft-reconfiguration inbound
    address-family ipv4 unicast
      send-community
      soft-reconfiguration inbound
  !
  neighbor 192.84.5.240
    inherit peer core_peers
  neighbor 192.84.5.250
    inherit peer core_peers

You can see that peer groups become templates and the parameters for each address family with a peer are configured under the peer (as part of the template) rather than the address family block directly under the BGP process.

Monday 18 May 2015

Compiling GNS3 under Linux

I recently had cause to run GNS3 on Linux as I needed to support a cloud interface using VLANs: I needed to link connections to some virtual routers out onto a physical interface, with each link as a separate VLAN.  OS X doesn't support this (it seems - you can configure it, but it doesn't appear to work), whereas Linux does.

More on that later, but I found this guide very useful for setting up GNS3 on Ubuntu 14.04 Desktop and it worked fine in a VMware VM on my laptop:

http://www.firstdigest.com/2014/12/gns3-1-2-1-installation-on-ubuntu-14-04/