Huawei Quidway S5600 Series Operation Manual page 348

Operation Manual – Routing Protocol
Quidway S5600 Series Ethernet Switches-Release 1510
II. Open
Open massage is used to establish connections between BGP speakers. It is sent
when a TCP connection is just established. Figure 5-2 shows the format of an Open
message.
0
Version
My Autonomous System
Opt Parm Len
Figure 5-2 BGP Open message format
The fields are described as follows.
Version: BGP version. As for BGP-4, the value is 4.
My Autonomous System: Local AS number. By comparing this filed of both sides,
a router can determine whether the connection between itself and the BGP peer is
of EBGP or IBGP.
Hold time: Hold time is to be determined when two BGP speakers negotiate for the
connection between them. The Hold times of two BGP peers are the same. A BGP
speaker considers the connection between itself and its BGP peer to be
terminated if it receives no Keepalive or Update message from its BGP peer
during the hold time.
BGP Identifier: The IP address of a BGP router.
Opt Parm Len: The length of the optional parameters. A value of 0 indicates no
optional parameter is used.
Optional Parameters: Optional parameters used for BGP authentication or
multi-protocol extensions.
III. Update
Update message is used to exchange routing information among BGP peers. It can
propagate a reachable route or withdraw multiple pieces of unreachable routes. Figure
5-3 shows the format of an Update message.
Network Layer Reachability Information (variable)
Figure 5-3 BGP Update message format
7 15
Hold Time
BGP Identifier
Optional Parameters
Unfeasible Routes Length (2 bytes)
Withdrawn Routes (variable)
Total Path Attribute Length (2 bytes)
Path Attributes (variable)
Huawei Technologies Proprietary
5-3
Chapter 5 BGP Configuration
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