Mpls Maximum Transmission Unit; Label Security For Bgp Inter-As Option-B; How To Implement Mpls Forwarding; Configuring Mpls Label Security - Cisco ASR 9000 Series Configuration Manual
Aggregation services router mpls
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Also See for ASR 9000 Series:
- Command reference manual (1138 pages) ,
- Routing configuration manual (702 pages) ,
- Reference manual (696 pages)
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MPLS Maximum Transmission Unit
• Imposition
• Disposition
• Label swapping
MPLS Maximum Transmission Unit
MPLS maximum transmission unit (MTU) indicates that the maximum size of the IP packet can still be sent
on a data link, without fragmenting the packet. In addition, data links in MPLS networks have a specific MTU,
but for labeled packets. All IPv4 packets have one or more labels. This does imply that the labeled packets
are slightly bigger than the IP packets, because for every label, four bytes are added to the packet. So, if n is
the number of labels, n * 4 bytes are added to the size of the packet when the packet is labeled. The MPLS
MTU parameter pertains to labeled packets.
Label Security for BGP Inter-AS Option-B
Option-B is a method to exchange VPNv4/VPNv6 routes between Autonomous Systems (AS), as described
in RFC-4364. When the local router that has Option-B peering with other autonomous systems receives a
labeled packet from an external peer, the local router ensures the following:
• the top label is advertised to the source of traffic
• label stack on the packet received from the external peer contains at least one label (explicit null label
How to Implement MPLS Forwarding
These topics explain how to configure a router for MPLS forwarding.
Configuring MPLS Label Security
Perform this task to configure the MPLS label security on the interface.
SUMMARY STEPS
1. configure
2. interface type interface-path-id
3. mpls label-security rpf
4. Use the commit or end command.
Cisco ASR 9000 Series Aggregation Services Router MPLS Configuration Guide, Release 4.3.x
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is not included)
Implementing MPLS Forwarding
OL-28381-02
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