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SONiC hands-on training - Module 5 - Lab 2 – BGP Configuration

You are a network engineer tasked with configuring a simple BGP (Border Gateway Protocol) routing protocol in a triangular topology involving three routers:

  • Router 1,
  • Router 2
  • Router 3.

The routers are connected via Ethernet interfaces, as shown in the diagram.

Instruction 

Step 1: Assign IP Addresses on all of the Routers. 

Log in to the switches (Router 1, Router 2, Router 3) using the default credentials, use the Klish CLI. Assign a proper IP Addressess to each of the port that is connected to other Router. Create an Loopback interface and assign a IP address to that interface. 

Router 1: 

  • Ethernet 1 – 1.1.1.1/31 
  • Ethernet 8 – 1.1.1.2/31 
  • Loopback0 – 192.168.0.1/32 

Router 2: 

  • Ethernet1 – 1.1.1.4/31 
  • Ethernet8 – 1.1.1.3/31 
  • Loopback0 – 192.168.0.2/32 

Router 3 

  • Ethernet1 – 1.1.1.0/31 
  • Ethernet8 – 1.1.1.5/31 
  • Loopback0 – 192.168.0.3/32 

Step 2: Create BGP on every router with different AS number and configure a router id for the BGP process 

After you configured all of the interfaces on the router, you need to create an BGP process on a every router and configure a proper router-id on every router with created BGP session. 

Step 3: Activate IPv4 unicast address-family and configure every neighbor. 

Activate address-family on every BGP session – This must be done on the neighbours (IPv4 unicast address family). You will need to advertise local interfaces, also in the IPv4 unicast address-family. 

Step 4: Verify BGP configuration. 

You need to check the BGP configuration after the configuration – Make sure everything is set all right! To do that, you need to type in console “show bgp ipv4 unicast summary” 

Step 5: Do the connectivity test. 

From each router, ping the Loopback interfaces of the other two routers to confirm end-to-end connectivity

  • Default credentials: admin / YourPaSsWoRd 
  • Be cautious about the BGP AS number that you are using – In this case, it needs to be different! 
  • Double-check every IP address if they are assigned correctly! 
  • The names of the virtual computers are different in remote access to those shown on the topology. Virtual computers and their counterparts in remote access are motioned below:
    • SW1 – mod5lab1-sw1
    • SW2 – mod5lab1-sw2
    • SW3 – mod5lab1-sw3

The purpose of the laboratory is to practice creating MCLAGs and PortChannels and how to use them in real environment. 

Step 1: Assign IP Addresses on all of the Routers. 

Router 1 

interface Loopback 0 

 ip address 192.168.0.1/32 

interface Ethernet1  

 ip address 1.1.1.1/31  

 no shutdown 

interface Ethernet8  

 ip address 1.1.1.2/31  

 

Router 2 

 interface Loopback 0 

 ip address 192.168.0.2/32 

interface Ethernet1  

 ip address 1.1.1.4/31  

 no shutdown 

interface Ethernet8  

 ip address 1.1.1.3/31  

 no shutdown 

 

Router 3 

interface Loopback 0 

 ip address 192.168.0.3/32 

interface Ethernet1  

 ip address 1.1.1.0/31  

 no shutdown 

interface Ethernet8  

 ip address 1.1.1.5/31  

 no shutdown 

 

 

Step 2 & 3: Create BGP on every router with different AS number, configure a router id for the BGP process, activate address-family and configure every neighbor. 

Router 1  

router bgp 65100  

 router-id 192.168.0.1 

 address-family ipv4 unicast 

  redistribute connected 

 

 neighbor 1.1.1.0 

  remote-as 65102 

  address-family ipv4 unicast 

   activate 

 

 neighbor 1.1.1.3 

  remote-as 65101 

  address-family ipv4 unicast 

   activate 

 

Router 2  

routerbgp 65101  

 router-id 192.168.0.2 

 address-family ipv4 unicast 

  redistributeconnected 

  

 neighbor 1.1.1.2 

  remote-as 65100 

  address-family ipv4 unicast 

   activate 

  

 neighbor 1.1.1.5 

  remote-as 65102 

  address-family ipv4 unicast 

   activate 

Router 3  

routerbgp 65102  

 router-id 192.168.0.3 

 address-family ipv4 unicast 

  redistributeconnected 

  

neighbor 1.1.1.1 

  remote-as 65100 

  address-family ipv4 unicast 

   activate 

  

neighbor 1.1.1.4 

  remote-as 65101 

  address-family ipv4 unicast 

   activate 

  

Step 4: Verify BGP Configuration 

show bgp ipv4 unicast summary example: 

sonic# show bgp ipv4 unicast summary 

BGP router identifier 1.1.1.1, local AS number 100 

Neighbor    V AS MsgRcvd MsgSent InQ OutQ Up/Down State/PfxRcd 

192.168.0.2 4 200 18480  18486    0 0      1w5d19h     8 

192.168.0.3 4 200 18510  18502    0 0     02:49:01     11 

 

Step 5: Check the connectivity between the routers. 

 Router 1: 

# Ping Router 2’s Loopback 

ping 192.168.0.2 

# Ping Router 3’s Loopback 

ping 192.168.0.3 

# Ping Router 2’s Ethernet Interface (1.1.1.4) 

ping 1.1.1.4 

# Ping Router 3’s Ethernet Interface (1.1.1.0) 

ping 1.1.1.0 

 

Expected Output: 

All pings should show success with low latency 

Router 2: 

# Ping Router 1’s Loopback 

ping 192.168.0.1 

# Ping Router 3’s Loopback 

ping 192.168.0.3 

# Ping Router 1’s Ethernet Interface (1.1.1.1) 

ping 1.1.1.1 

# Ping Router 3’s Ethernet Interface (1.1.1.5) 

ping 1.1.1.5 

 

Expected Output: 

All pings should show success with low latency 

Router 3: 

# Ping Router 1’s Loopback 

ping 192.168.0.1 

# Ping Router 2’s Loopback 

ping 192.168.0.2 

# Ping Router 1’s Ethernet Interface (1.1.1.2) 

ping 1.1.1.2 

# Ping Router 2’s Ethernet Interface (1.1.1.3) 

ping 1.1.1.3 

 

Expected Output: 

All pings should show success with low latency