Figure 39 TLV Type 22 Format

0 1

2

3

012345073901234

567E90123

4 5 6 7 3 9 0 1

System ID and pseudonode number

...System ID and pseudonode (continued)

Link metric

Link metric (continued)

Sub-TLV/ length

Sub-TLVs, h

The field for systemID and pseudonode number is 7 bytes (56 bits) long. The default link metric is 3 bytes long. The sub-TLV length field is also 1 byte long. It indicates the length of the total number of sub-TLVs.

Table 3-5 describes the seven different sub-TLVs that carry MPLS Traffic Engineering link information.

Table 3-5. Sub-TLVs That Carry MPLS Traffic Engineering Link Information

Sub-TLV Name

Sub-TLV ID

Size

Definition

Interface Configuration

Attribute flags

3

4 bytes

32-bit bitmask that puts the link in one or more administrative groups

mpls traffic-eng attribute-flags

IPv4 interface address

6

4 bytes

Interface mask is in the Type-22 TLV

ip address network mask

IPv4 neighbor address

8

4 bytes

IP address of a neighbor on a p2p link; 0.0.0.0 if describing a broadcast link

N/A

Maximum link bandwidth

9

4 bytes

Maximum physical bandwidth on the interface, as seen in sh int and optionally set with the bandwidth command

bandwidth x

Maximum reservable bandwidth

10

4 bytes

Amount of bandwidth that can be reserved on the link

ip rsvp bandwidth x

Unreserved bandwidth (per priority level)

11

bytes

For each priority level, the difference between the maximum reservable bandwidth and the reserved bandwidth per priority

N/A

Traffic engineering metric

18

3 bytes

The IS-IS cost of the link, or a cost assigned by the TE code

isis metric or mpls traffic-eng administrative-weight

If you compare IS-IS to OSPF, you see that although the packet formats are different, both protocols advertise exactly the same information.

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