Opaque LSA

EdTheLad

As per below, anyone know what the Opaque ID 0 is used for? it has 0 links, not sure what it represents?


R3#sh ip ospf database opaque-area self-originate

OSPF Router with ID (3.3.3.3) (Process ID 1)

Type-10 Opaque Link Area Link States (Area 0)

LS age: 1850
Options: (No TOS-capability, DC)
LS Type: Opaque Area Link
Link State ID: 1.0.0.0
Opaque Type: 1
Opaque ID: 0
Advertising Router: 3.3.3.3
LS Seq Number: 80000026
Checksum: 0x16DE
Length: 28
Fragment number : 0

MPLS TE router ID : 3.3.3.3

Number of Links : 0

LS age: 1349
Options: (No TOS-capability, DC)
LS Type: Opaque Area Link
Link State ID: 1.0.0.1
Opaque Type: 1
Opaque ID: 1
Advertising Router: 3.3.3.3
LS Seq Number: 8000002C
Checksum: 0x5641
Length: 132
Fragment number : 1

Link connected to Point-to-Point network
Link ID : 4.4.4.4
Interface Address : 10.0.34.3
Neighbor Address : 10.0.34.4
Admin Metric : 100
Maximum bandwidth : 12500000
Maximum reservable bandwidth : 0
Number of Priority : 8
Priority 0 : 0 Priority 1 : 0
Priority 2 : 0 Priority 3 : 0
Priority 4 : 0 Priority 5 : 0
Priority 6 : 0 Priority 7 : 0
Affinity Bit : 0x0
IGP Metric : 100

Number of Links : 1

LS age: 1350
Options: (No TOS-capability, DC)
LS Type: Opaque Area Link
Link State ID: 1.0.0.2
Opaque Type: 1
Opaque ID: 2
Advertising Router: 3.3.3.3
LS Seq Number: 80000027
Checksum: 0x584
Length: 132
Fragment number : 2

Link connected to Point-to-Point network
Link ID : 1.1.1.1
Interface Address : 10.0.13.3
Neighbor Address : 10.0.13.1
Admin Metric : 10
Maximum bandwidth : 12500000
Maximum reservable bandwidth : 0
Number of Priority : 8
Priority 0 : 0 Priority 1 : 0
Priority 2 : 0 Priority 3 : 0
Priority 4 : 0 Priority 5 : 0
Priority 6 : 0 Priority 7 : 0
Affinity Bit : 0x0
IGP Metric : 10

Number of Links : 1

fredrikjj

It distributes the TE router-id. There are two types of TLVs that are used in the opaque LSAs for TE, type 1 and type 2. Type 1 is the one you see with the MPLS-TE router-id and 0 links. Type 2 contains the sub-TLVs for each link where each sub-TLV describes some aspect of it like attribute flags, te metric, bandwidth, etc. So basically, each router will have one type 1 and then one type 2 for every link that has TE enabled. My reference is the book Traffic Engineering with MPLS, chapter 3.