D-Link DGS-3312SR [155/290] State advert mats

D-Link DGS-3312SR [155/290] State advert mats
DGS-3312SR Stackable Gigabit Layer 3 Switch
Version No.
Packet Length
Router ID
Area ID
Authentication Type
Authentication
Authentication
Checksum
Link-State Acknowledgment Packet
5
Link-State Advertisement Header ...
Figure 5- 24. Link-State Acknowledgment Packet
Each acknowledged link-state a ent header. It contains all the
information required to uniquely id
Link isement For
There types of link-state a link-
state advertisement header. Succeeding se
Each link-state advertisement describes r links
advertisement. In addition, whenever th k links
advertisement. Other types of link-state ad d. The flooding algorithm is reliable, ensuring
that all rou llection of lin e link-
state
From the link-state database, each router c outing table.
There are four types of link state advertisem
Router Links Advertisements
Network Links Advertis
Summary Link Advertisements
s System Li
All link state advertisements begin with a common 20-byte header. This header contains enough information to uniquely
identify the advertisements (Link State Type, Link State ID, and Advertising Router). Multiple instances of the link state
advertisement may exist in the routing domain at the same time. It is then necessary to determine which instance is more
recent. This is accomplished by examining the link state age, link state sequence number and link state checksum fields
that are also contained in the link state advertisement header.
The format of the Link State Advertisement Header is shown below:
dvertisement is described by its link-state advertisem
entify both the advertisement and the advertisement’s current instance.
-State Advert mats
are five distinct dvertisements. Each link-state advertisement begins with a standard 20-byte
ctions then diagram the separate link-state advertisement types.
a piece of the OSPF routing domain. Every router originates a route
e router is elected as the Designated Router, it originates a networ
vertisements may also be originate
ters have the same co
(or topological) database.
k-state advertisements. The collection of advertisements is called th
onstructs a shortest path tree with itself as root. This yields a r
ents, each using a common link state header. These are:
ements
Autonomou nk Advertisements
Link State Advertisement Header
142

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