What is VRF? Its Advantages & Show Commands!

VRF: A saviour for ISP Infrastructure

Hey there readers, in this blog today we are going to learn about an amazing superhero who is there to rescue the ISP (Internet Service Providers) from the troubles they might face because of their infrastructure. So, let’s get started and understand?what is VRF.

What is VRF?

VRF stand for Virtual Routing and Forwarding. This technology is there to allow you to create multiple routing tables within a router rather than just having a single Global Routing table. In order to understand it in a simpler way, we can say that it is somewhat similar to what a VLAN is there for in switching. There are some specific exceptions but let's keep things simple for now.?With VLANs, you virtualize a single switch into multiple virtual switches. With VRFs, you virtualize a single router into multiple virtual routers.?If to learn VRF in-depth, then here is the blog you must read - Everything you need to know about VRF by PyNet Labs.

Advantages of Using Virtual Routing and Forwarding

There are multiple reasons why you would prefer using Virtual Routing and Forwarding in an ISP infrastructure or in your LAN.

-????????By using VRF we can create multiple routing tables rather than just having one global routing table. This makes the management of traffic better.

-????????Can be used to deploy MP BGP and MPLS in WAN Infrastructure.

-????????It can help in improving the network functionality by allowing users to segment network paths without actually using multiple routers.

-????????It allows the virtual creation of multiple routes instated on one physical device.

Now, let’s have a look at the commands related to VRF for the following configurations:

For the Creation of VRF Instances:

• R1(config-vrf)#ip vrf CustomerA
• R1(config-vrf)#exit
• R1(config)#ip vrf CustomerB
• R1(config-vrf)#exit

For Applying VRF to Interfaces:

• R1(config)#interface gi 0/0
• R1(config-if)#ip vrf forwarding CustomerA
• R1(config-if)#ip address 192.168.1.1 255.255.255.0
• R1(config-if)#no shutdown

For Applying Routing to VRF

Static Route

• R1(config)# ip route vrf CustomerA 10.1.1.0 255.255.255.0 192.168.1.1

BGP

• R1(config)#router bgp <local_as>
• R1(config-router)#address-family ipv4 vrf <vrf_name>
• R1(config-router-af)# neighbor <remote_addr> remote <remote_as>

Example

• router bgp 100
• ?address-family ipv4 vrf VRF-1
• ?neighbor 200.10.1.2 remote-as 200
• ?neighbor 200.10.1.2 activate
• ?no auto-summary
• ?no synchronization
• ?network 192.168.1.1 mask 255.255.255.255
• ?exit-address-family

EIGRP

• R1(config)# router eigrp <ASNUMBER>
• R1(config)# address-family ipv4 vrf <VRFNAME>
• R1(config)# network <IPADDRESS> <WILDCARD>
• R1(config)# autonomous-system <ASNUMBER>

OSPF

• R1(config)# router ospf PID vrf VRFNAME
• R(config)# network x.x.x.x??0.0.0.255 area AREANUMBER

Some show commands which can be used to check the details related to the VRF

To help you understand VRF better, here is the video you must watch.

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