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C
HAPTER
30: C
ONFIGURING
BGP
The BGP system runs on a specific router as a high layer protocol. At system
startup, the whole BGP routing table is transmitted for the exchange of routing
information. Later on, only an update message is transmitted for updating the
routing table. In the system, keep-alive messages are received and transmitted to
check whether the connection between routers is normal.
The router transmitting the BGP message is called the BGP speaker. It receives and
generates new routing information from time to time and advertises to other BGP
speakers. When a BGP speaker receives a new route advertisement from other
ASs, if this route is better than the existing route, or if there is no acceptable route
currently, the BGP speaker broadcasts this route to all other BGP speakers in the
AS. BGP speakers are peers to each other and several related peers form a peer
group.
BGP runs on the router in two modes:
■
IBGP (Internal BGP)
■
EBGP (External BGP)
IBGP is run when routers in an autonomous system exchange network reachable
information. When routers of different ASs exchange network reachable
information, they use EBGP.
The BGP protocol system is driven by messages that can be divided into 4
categories:
■
Open message. This is the first transmitted message after the connection is
created. It is used to create a connection between BGP peers
■
Update message is the most important message in BGP system, and is used to
switch routing information among the peers. Update message consists of three
parts: unreachable route, path attributes and Network Layer Reachability
Information (NLRI).
■
Notification message notifies errors.
■
Keep-alive message is used to check the validity of the connection.
Configuring BGP
A BGP configuration includes tasks described in the following sections:
■
Enabling BGP
■
Configuring Networks for BGP Distribution
■
Configuring Peers
A BGP advanced configuration includes:
■
Setting the MED for the AS
■
Allow Comparing Path MED
■
Configuring the Local Preference
■
Configuring BGP Timers
■
Configuring a BGP Peer Group
■
Creating Aggregate Addresses
■
Configure BGP Route Reflector
Содержание 3036
Страница 1: ...http www 3com com 3Com Router Configuration Guide Published March 2004 Part No 10014299 ...
Страница 4: ...VPN 615 RELIABILITY 665 QOS 681 DIAL UP 721 ...
Страница 6: ...2 ABOUT THIS GUIDE ...
Страница 7: ...I GETTING STARTED Chapter 1 3Com Router Introduction Chapter 2 3Com Router User Interface ...
Страница 8: ...4 ...
Страница 16: ...12 CHAPTER 1 3COM ROUTER INTRODUCTION ...
Страница 34: ...30 ...
Страница 60: ...56 CHAPTER 3 SYSTEM MANAGEMENT ...
Страница 88: ...84 CHAPTER 5 CONFIGURING NETWORK MANAGEMENT RouterA interface ethernet 0 RouterA Ethernet0 rmon promiscuous ...
Страница 98: ...94 CHAPTER 6 DISPLAY AND DEBUGGING TOOLS ...
Страница 110: ...106 ...
Страница 114: ...110 CHAPTER 8 INTERFACE CONFIGURATION OVERVIEW ...
Страница 158: ...154 CHAPTER 10 CONFIGURING WAN INTERFACE ...
Страница 168: ...164 ...
Страница 188: ...184 CHAPTER 13 CONFIGURING PPPOE CLIENT ...
Страница 192: ...188 CHAPTER 14 CONFIGURING SLIP Router ip route static 0 0 0 0 0 0 0 0 10 110 0 1 ...
Страница 248: ...244 CHAPTER 16 CONFIGURING LAPB AND X 25 ...
Страница 292: ...288 CHAPTER 18 CONFIGURING HDLC Enable HDLC packet debugging debugging hdlc packet interface type number ...
Страница 320: ...316 ...
Страница 330: ...326 CHAPTER 20 CONFIGURING IP ADDRESS ...
Страница 362: ...358 CHAPTER 21 CONFIGURING IP APPLICATION ...
Страница 374: ...370 CHAPTER 23 CONFIGURING IP COUNT ...
Страница 406: ...402 CHAPTER 25 CONFIGURING DLSW ...
Страница 408: ...404 ...
Страница 452: ...448 CHAPTER 29 CONFIGURING OSPF ...
Страница 482: ...478 CHAPTER 30 CONFIGURING BGP ...
Страница 494: ...490 CHAPTER 31 CONFIGURING IP ROUTING POLICY ...
Страница 502: ...498 ...
Страница 508: ...504 CHAPTER 33 IP MULTICAST ...
Страница 514: ...510 CHAPTER 34 CONFIGURING IGMP ...
Страница 526: ...522 CHAPTER 36 CONFIGURING PIM SM ...
Страница 528: ...524 ...
Страница 532: ...528 CHAPTER 37 CONFIGURING TERMINAL ACCESS SECURITY ...
Страница 550: ...546 CHAPTER 38 CONFIGURING AAA AND RADIUS PROTOCOL ...
Страница 590: ...586 CHAPTER 40 CONFIGURING IPSEC ...
Страница 599: ...IX VPN Chapter 42 Configuring VPN Chapter 43 Configuring L2TP Chapter 44 Configuring GRE ...
Страница 600: ...596 ...
Страница 638: ...634 CHAPTER 43 CONFIGURING L2TP ...
Страница 649: ...X RELIABILITY Chapter 45 Configuring a Standby Center Chapter 46 Configuring VRRP ...
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Страница 666: ...662 ...
Страница 670: ...666 CHAPTER 47 QOS OVERVIEW ...
Страница 700: ...696 CHAPTER 49 CONGESTION MANAGEMENT ...
Страница 706: ...702 CHAPTER 50 CONGESTION AVOIDANCE ...
Страница 707: ...XII DIAL UP Chapter 51 Configuring DCC Chapter 52 Configuring Modem ...
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Страница 762: ...758 CHAPTER 52 CONFIGURING MODEM ...