MPLS QOS EXPERIMENTAL BITS


Hi All,

After the first unsuccessful CCIE R&S lab attempt in Belgium in my last post I said I was having a little trouble with the MPLS VPN configuration and it most certainly was not because I did not know what ingredients were necessary in order to configure the tunnel between the sites but because the way Cisco asked me to configure it and manipulate the traffic  , it made me think really hard for a long while during the exam (almost 1hr) and it cost me very dearly in the end ! Windows-Logic

 

 

 

Below topology is from INE SPv3 (Service Provider) video series with Brian McGahan who I’m sure we all know and love to listen to.

mpls_exce_sp_ine

This is how it is presented to us in GNS3

mpls_exce_sp

 

GNS3_NET_FILE  : MPLS_QOS_NET_FILE

GNS3 INITIAL CONFIGS : impls_initial_configs

Cisco 12000 series router’s XR_1 and XR_2 are simulated by 3745 routers – these devices are not supported in GNS3 so rack rental is a must.  exam_funny

Some of you might be asking yourself right now why would I create a post that revolves around MPLS QOS ?? Well , short answer is “be prepare to get stuck in your lab exam ” because even if you get really simple MPLS requirements  , they will definitely confuse you with something else. CCIE lab as we all know is not about best practises and myself having finally experienced it , it is miles away from there , it is about whether you can accomplish given task and meet the requirements or not !

One more thing , make sure you experiment with as many commands as possible (some of the I’ve listed below) and understand how they work and affect the network because even if you manage to get your MPLS VPN Tunnel up and running but you do it not how they asked you to , you will fail the whole section !

mpls ldp router-id Loopback0
mpls ip propagate-ttl
mpls ldp autoconfig
bgp default ipv4-unicast
address-family vpnv4
address-family ipv4 vrf
redistribution within MPLS backbone – especially when you have two different IGPs running inside where you first have to correctly redistribute between them in order to make you BGP/MPLS operational then most likely you will need to do some more redistribution between PE-CE to make it all work !

 

In summary –  MPLS is intense , it is great fun though !

Enjoy !

Tom