MPLS

Router generates local labels for each network in the routing table, and advertises to adjacent routers.

MPLS labels are locally significant to the router

• A label is created for each IP destination
• Neighbors use the labels learned from their neighbors
• Labels of directly connected neighbors need to be known

LDP - Label distribution protocol

LSP - Label switch path

LSR - Label switch router

Labels added to packets at layer 2.5

Routers swap the label, don’t need to look at layer 3 information.

IPv6 can go over IPv4 network.

Labels are 32 bits

• 20 Bits Label
• 3 bit Experimental (QoS)
• 1 bit bottom of stack (set to 1, top/transit label set to 0)
• 8 bits TTL

Labels 0-15 are reserved

imp-null (3) Directly connected

PHP - Penultimate hop popping - remove label before it hits the final router. (Default)

mpls ip

int gi1/0 
	mpls ip


show mpls ldp bindings 5.5.5.5 32
show mpls forwarding-table 5.5.5.5

Constrain range of labels: mpls label range 100 199

Transport Address

Router ID by default, is the transport address

1. Configured
2. Highest IP on loopback
3. Highest IP on Interface

int g2/0
	mpls ldp discovery transport-address interface

VRF Utilities

ping vrf 101:ACME 172.16.101.2
traceroute vrf 101:ACME 172.16.101.2

traceroute mpls ipv4 5.5.5.5 255.255.255.255

show ip route vrf 101:ACME
ip route vrf 101:ACME 10.10.10.0 255.255.255.0 172.16.101.2

MPLS Layer 2 VPNs

Service to allow Layer 2 connectivity between customer sites. * VPWS - Virtual Private Wire Service * Point-to-point connection * Can use L2TPv3 over an IP network * Can use MPLS for the transport (AToM) * AToM - Any Transport over MPLS * subset of VPWS * Supports Ethernet, PPP, HDLC, Frame Relay, and ATM. Advantages to

CG1NETWORKCraig Garnham

MPLS Layer 3 VPNs

* Routing protocol between PE and CE to learn customer routes * VRF - Virtual Routing and Forwarding * VPNv4 Route - Information added to routes to identify the customer * mBGP used to exchange VPNv4 routes between PE routers * No encryption on traffic PE to PE mBGP router bgp 65536 neighbor 5.5.

CG1NETWORKCraig Garnham