Shulou(Shulou.com)06/01 Report--

Large and small network construction-BGP plus experimental verification BGP

-definition

-Overview

-principle

# create a neighbor table

# synchronize the database:

Network {exact route entry}

Import-route {protocol}

The status of each entry in the BGP database must be:

Which means "best-the best".

1. Try to put it in your own routing table

two。 Send it to your own BGP neighbor

# calculate the routing table

-message

Open: contains the parameters that BGP needs to negotiate when establishing a neighbor

Update: contains BGP routing entries

Keep-alive: used to send periodically and maintain neighbor relationship

Notification: notification message. Used to notify error messages

The structure and function of BGP # BGP is used to exchange routing information between different autonomous systems (AS). When two AS need to exchange routing information, each AS must specify a node running BGP to exchange routing information with other AS on behalf of AS. This node can be a host. But it is usually the router that performs the BGP. Two AS routers that use BGP to exchange information are also known as border gateways (Border Gateway) or border routers (Border Router) # because they may be connected to different AS, there may be multiple border routers running BGP within an AS. A BGP running between two or more peer entities in the same autonomous system (AS) is called an IBGP (Internal/Interior BGP). A BGP running between peer entities that belong to different AS is called EBGP (External/Exterior BGP). A router that exchanges information with other AS at the AS boundary is called a border router (border/edge router). In the Internet operating system (Cisco IOS), routes advertised by IBGP have a distance of 200and have a lower priority than routes advertised by EBGP and any Interior Gateway Protocol (IGP). In other router implementations, the priority order is EBGP over IGP, and IGP over IBGP. # BGP belongs to the external gateway routing protocol, which can realize inter-domain routing without loop between autonomous systems. BGP is the main routing protocol to communicate Internet wide area network. For example, routing between different provinces and different countries mostly depends on BGP protocol. BGP can be divided into IBGP (Internal BGP) and EBGP (External BGP). The neighbor relationship (or communication peer / peer entity) of BGP is implemented through manual configuration, and peer entities exchange data through TCP (port 179) sessions. The BGP router periodically sends 19-byte keep-alive keep-alive messages to maintain the connection (the default period is 30 seconds). Among the routing protocols, only BGP uses TCP as the transport layer protocol. BGP peer:

IBGP neighbor

EBGP neighbor

# establish neighbors through directly connected ports;-- not very stable

# establish neighbors through non-directly connected interfaces;-- very stable

"Update source detection" mechanism-both IBGP and EBGP need to consider "directly connected detection mechanism"-only when establishing a non-directly connected EBGP

When you are a neighbor, you need to think about it.

That is, when an EBGP neighbor is established, a

IP address of the directly connected physical interface

(the TTL of messages between 1.ebgp neighbors is 1;)

(2. Direct connection detection mechanism: when going to the other party's address)

(directly connected routing must be used.)

Configuration of R1

Undo ter mo

System-v

Sysname R1

Interface loopback 0

Ip address 10.10.1.1 255.255.255.255

Q

Interface gi0/0/0

Ip address 192.168.12.1 255.255.255.0

Q

Configuration of R2

Undo ter mo

System-v

Sysname R2

Interface loopback 0

Ip address 10.10.2.2 255.255.255.255

Q

Interface gi0/0/1

Ip address 192.168.12.2 255.255.255.0

Q

Inter gi0/0/0

Ip address 192.168.23.2 255.255.255.0

Q

Configuration of R3

Undo ter mo

System-v

Sysname R3

Interface loopback 0

Ip address 10.10.3.3 255.255.255.255

Q

Interface gi0/0/1

Ip address 192.168.23.3 255.255.255.0

Q

Inter gi0/0/0

Ip address 192.168.34.3 255.255.255.0

Q

Configuration of R4

Undo ter mo

System-v

Sysname R4

Interface loopback 0

Ip address 10.10.4.4 255.255.255.255

Q

Interface gi0/0/1

Ip address 192.168.34.4 255.255.255.0

Q

Inter gi0/0/0

Ip address 192.168.45.4 255.255.255.0

Q

Configuration of R5

Undo ter mo

System-v

Sysname R5

Interface loopback 0

Ip address 50.50.50.50 255.255.255.255

Q

Interface gi0/0/1

Ip address 192.168.45.5 255.255.255.0

Q

~ AS 234 internal configuration ~

1. Configure IGP=RIP

R2:

Rip

Version 2

Network 192.168.23.0

Network 10.0.0.0

Q

R3:

Rip

Version 2

Network 192.168.23.0

Network 192.168.34.0

Network 10.0.0.0

Q

R4:

Rip

Version 2

Network 192.168.34.0

Network 10.0.0.0

Q

Configuration of 2.BGP: non-directly connected IBGP neighbor relationship-R2R4

R2:

Bgp 234

Router-id 2.2.2.2

Peer 10.10.4.4 as-number 234

Peer 10.10.4.4 connect-interface loopback 0

R4:

Bgp 234

Router-id 4.4.4.4

Peer 10.10.2.2 as-number 234

Peer 10.10.2.2 connect-interface loopback 0

~ AS 234 and AS 500 ~

Configuration of 1.BGP: "directly connected" EBGP between R4--R5

R4:

Bgp 234

Peer 192.168.45.5 as-number 500

R5:

Bgp 500

Router-id 5.5.5.5

Peer 192.168.45.4 as-number 234

2.R5 announces routes through Network

Bgp 500

Network 50.50.50.50 255.255.255.255

~ AS 234 and AS 100 ~

1. Create loopback 12 to establish EBGP neighbor relationships that are not directly connected

R2:

Interface loopback 12

Ip address 10.12.12.2 255.255.255.255

Quit

Ip route-static 10.12.12.1 255.255.255.255 192.168.12.1

R1:

Interface loopback 12

Ip address 10.12.12.1 255.255.255.255

Quit

Ip route-static 10.12.12.2 255.255.255.255 192.168.12.2

two。 Create a non-directly connected EBGP neighbor relationship:

R1:

Bgp 100

Peer 10.12.12.2 as-number 234

Peer 10.12.12.2 connect-interface loopback 12

Peer 10.12.12.2 ebgp-max-hop 20

R2:

Bgp 234

Peer 10.12.12.1 as-number 100

Peer 10.12.12.1 connect-interface loopback 12

Peer 10.12.12.1 ebgp-max-hop 20

3. Declare a route on R1 through import-route

R1:

Bgp 100

Import-route direct-> announces 10.10.1.1Comp32 to enter BGP

~ ~ routing delivery between AS 100s and AS 500s ~ ~

Before the next configuration command, you should first check: display bgp routing-table-> check the database of BGP

The status of 50.50.50.50 in the BGP database above R2 is not excellent.

10.10.1.1 in the BGP database above R4: 32 status, not excellent

Reason:

For 50.50.50.50 Universe 32 in R2's BGP database

Its next-hop IP address: 192.168.45.5, is unreachable by route.

For 10.10.1.1 / 32 in the BGP database of R4

Its next hop IP address is 10.12.12.1, which is unreachable by route.

Solution:

1. Configure on R4:

Rip

The purpose of import-route direct-> is to introduce 192.168.45.0 Universe 24.

two。 Configure in R2:

Rip

The purpose of import-route static-> is to introduce 10.12.12.1Comp32.

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