Network Links Advertisements - D-Link DGS-3600 Series User Manual

Link ID
Link Data
No. of TOS
TOS 0 Metric
For each link, separate metrics may be specified for each Type of Service (ToS). The metric for ToS 0 must always be included,
and was discussed above. Metrics for non-zero TOS are described below. Note that the cost for non-zero ToS values that are not
specified defaults to the ToS 0 cost. Metrics must be listed in order of increasing TOS encoding. For example, the metric for ToS
16 must always follow the metric for ToS 8 when both are specified.
Field
ToS
Metric

Network Links Advertisements

Network links advertisements are Type 2 link state advertisements. A network links advertisement is originated for each transit
network in the area. A transit network is a multi-access network that has more than one attached router. The network links
advertisement is originated by the network's Designated Router. The advertisement describes all routers attached to the network,
including the Designated Router itself. The advertisement's Link State ID field lists the IP interface address of the Designated
Router.
The distance form the network to all attached routers is zero, for all ToS. This is why the ToS and metric fields need not be
specified in the network links advertisement.
The format of the Network Links Advertisement is shown below:
®
xStack DGS-3600 Series Layer 3 Gigabit Ethernet Managed Switch
Identifies the object that this router link connects to. Value depends on the link's Type.
When connecting to an object that also originates a link state advertisement (i.e. another
router or a transit network) the Link ID is equal to the neighboring advertisement's Link
State ID. This provides the key for looking up an advertisement in the link state
database. Type Link ID: Neighboring router's Router ID. IP address of Designated
Router. IP network/subnet number. Neighboring router's Router ID
Contents again depend on the link's Type field. For connections to stub networks, it
specifies the network's IP address mask. For unnumbered point-to-point connection, it
specifies the interface's MIB-II ifIndex value. For other link types it specifies the router's
associated IP interface address. This latter piece of information is needed during the
routing table build process, when calculating the IP address of the next hop.
The number of different Type of Service (TOS) metrics given for this link, not counting
the required metric for TOS 0. If no additional TOS metrics are given, this field should be
set to 0.
The cost of using this router link for TOS 0.
Description
IP Type of Service that this metric refers to.
The cost of using this outbound router link, for traffic of the specified TOS.
Network Link Advertisements
Link-State Age
Link-State Checksum
Figure 8- 39. Network Link Advertisements
Options
Link-State ID
Advertising Router
Link-State Sequence Number
Network Mask
Attached Router
189
2
Length