D-Link DES-3350SR User Manual - page 120
D-Link DES-3350SR Standalone Layer 3 Switch
110
Options
The optional capabilities supported by the described portion of the
routing domain.
Link State Type
The type of the link state advertisement. Each link state type has a
separate advertisement format.
The link state type are as follows: Router Links, Network Links,
Summary Link (IP Network), Summary Link (ASBR), AS External Link.
Link State ID
This field identifies the portion of the internet environment that is being
described by the advertisement. The contents of this field depend on the
advertisement’s Link State Type.
Advertising Router
The Router ID of the router that originated the Link State Advertisement.
For example, in network links advertisements this field is set to the Router
ID of the network’s Designated Router.
Link State Sequence
Number
Detects old or duplicate link state advertisements. Successive instances
of a link state advertisement are given successive Link State Sequence
numbers.
Link State Checksum
The Fletcher checksum of the complete contents of the link state
advertisement, including the link state advertisement header by accepting
the Link State Age field.
Length
The length in bytes of the link state advertisement. This includes the 20-
byte link state advertisement header.
Router Links Advertisements
Router links advertisements are type 1 link state advertisements. Each router in an area originates a routers links advertisement.
The advertisement describes the state and cost of the router’s links to the area. All of the router’s links to the area must be
described in a single router links advertisement.
The format of the Router Links Advertisement is shown below:
Link-State Age
Options
Link-State Type
Link-State ID
Advertising Router
Link-State Sequence Number
Link-State Checksum
Length
Routers Links Advertisements
Reserved
Reserved
Number of Links
Link ID
Link Data
Type
No. Of TOS
TOS 0 Metric
TOS
Metric
...
TOS
Metric
...
Link ID
Link Data
0
0
V
B
E
Figure 9 - 23. Routers Links Advertisements
In router links advertisements, the Link State ID field is set to the router’s OSPF Router ID. The T - bit is set in the advertisement’s
Option field if and only if the router is able to calculate a separate set of routes for each IP Type of Service (TOS). Router links
advertisements are flooded throughout a single area only.
Field
Description