Archive for the ‘MPLS’ Category

We have VRF-lite setup on CE with multiple customer on single CE.In this case we are moving wan circuit from old PE to New PE.

After this migration we need to validate and compare route announced from CE to PE and its attributes(SOO,Local pref,Route-target). Number of announced route varies depending upon number of customer connected on CE so manual validation and comparison is tedious task

From router configuration we are creating script to capture pre and post migration logs on PE end by extracting network command used in each vrf BGP address-family on CE.(this step of pre/post check script preparation is done separately with migration config generation)
Below is the sample of the pre and post activity logs.


Announce route POSTTEST
Created GUI using tkinter for ease of use and non python user

Announce route compare GUI
Pre/post activity logs are provided as input to the program and empty excel file already configured with conditional formattingĀ to highlight unique values by comparing odd and even rows also provide as input in the background to the we get the output as excel file with errors highlighted automatically as shown in below excel screenshot.


With help of library textfsm we are able create table from above pre/post text file and with openpyxl we are writing it to excel sheet for comparison.Final output is below.

Link for the code

Annouce route comparision


Is MPLS layer 2.5 protocol

Posted: February 9, 2016 in MPLS

Simple answer is no as there is no layer 2.5 defined in standards but still we call MPLS as layer 2.5 protocol

1. MPLS label resides in front of layer 3 header and before layer 2 header
2. MPLS label are derived from IP routing table so we can say it is derived from layer 3 information butĀ  if we observe label swapping behavior is same like Ethernet header changes on every layer 3 hop

Benefits of MPLS

1. BGP free core
2. L2 and L3 MPLS vpn
3. MPLS traffic engg