The configuration of Route Policy with MED In MSR Series

The configuration of Route Policy with MED In MSR Series

Keywords: MSR; BGP4+;MED;Route Policy

I            Requirement for the diagram

This case will show you how to manage routing info based on BGP4+ and MED. All the router running BGP4+. IGP of AS200 import direct routing to make all router can communicate each other. RTA in AS100, RTB, RTC and RTD in AS200. EBGP was running on RTA,RTB,RTC; IBGP was running on RTB, RTC and RTD. Change the route from RTD to RTA by modify MED of RTA

Device List: 4 MSR;

CMW Version: Version 5.20, Beta 1105

 

II          Network topology

 

Figure 1 MED and Routing

III        Steps of configuration

1．RTA configuratioin：

#

 ipv6

#

//Set the MED attribute of RTA, Add acl and permit 1:1:1::/32

acl ipv6 number 2000

 rule 0 permit source 1:1:1::/32

#

interface Ethernet0/0

 port link-mode route

 ipv6 address 2::1/96

#

interface Ethernet0/1

 port link-mode route

 ipv6 address 1::1/96

#

interface LoopBack0

 ipv6 address 1:1:1::1/128

//BGP part

#

bgp 100

 undo synchronization

 #

 ipv6-family

  network 1:1:1::1 128

  import-route direct

  undo synchronization

  peer 1::2 as-number 200

  peer 2::2 as-number 200

//Apply apply_med_50 to interface which connect RTC（2::2)

Apply apply_med_100 to interface which connect RTB（1::2)

  peer 1::2 route-policy apply_med_100 export

  peer 2::2 route-policy apply_med_50 export

//define two routing policy, apply_med_50 and apply_med_100. The apply_med_50 is for 1:1:1::, set the MED value to 50, the apply_med_100, set MED value to 100

#

route-policy apply_med_50 permit node 10

 if-match acl 2000

 apply cost 50

route-policy apply_med_100 permit node 10

 if-match acl 2000

 apply cost 100

 

2．RTB configuration：

#

 ipv6

#

acl ipv6 number 2001

 rule 0 permit source 1:1:1::/96

#

interface Ethernet0/0

 port link-mode route

 ipv6 address 3::1/96

#

interface Ethernet0/1

 port link-mode route

 ipv6 address 1::2/96

 ip address 1.0.0.2 255.255.255.0

#

interface LoopBack0

 ipv6 address 2:2:2::2/128

//BGP part

#

bgp 200

 undo synchronization

 #

 ipv6-family

  network 2:2:2::2 128

  import-route direct

  undo synchronization

  peer 1::1 as-number 100

  peer 4::1 as-number 200

  peer 3::2 as-number 200

 

3．RTC configuration：

 

#

 ipv6

#

interface LoopBack0

 ipv6 address 3:3:3::3/128

#

interface GigabitEthernet0/0

 port link-mode route

 ipv6 address 2::2/96

 ip address 4.0.0.1 255.255.255.0

#

interface GigabitEthernet0/1

 port link-mode route

 ipv6 address 4::1/96

 ip address 1.0.0.3 255.255.255.0

//BGP part

#

bgp 200

 undo synchronization

 #            

 ipv6-family

  network 3:3:3::3 128

  import-route direct

  undo synchronization

  peer 3::1 as-number 200

  peer 2::1 as-number 100

  peer 4::2 as-number 200

 

4．RTD configuration：

 

#

 ipv6

#

interface LoopBack0

 ipv6 address 4:4:4::4/128

#

interface GigabitEthernet0/0

 port link-mode route

 ipv6 address 3::2/96

#

interface GigabitEthernet0/1

 port link-mode route

 ipv6 address 4::2/96

#

//BGP part

bgp 200

 undo synchronization

 #

 ipv6-family

  network 4:4:4::4 128

  import-route direct

  undo synchronization

  peer 3::1 as-number 200

  peer 4::1 as-number 200

IV       Key notes in the configuration

After apply route policy under interface of RTA, we need run command  reset bgp ipv6 all reset the state of BGP.

V         Result Check

1) From configuration above, the MED of routing to 1:1:1::1 that RTC  learned is lower that RTB, therefore, RTD will choose from RTD.

2) Tracert 1:1:1::1 from RTD, there has info below:

<RTD-3020>tracert ipv6 1:1:1::1        

    traceroute to 1:1:1::1 30 hops max,60 bytes packet, press CTRL_C to break

 1 3::1 2 ms 2 ms 1 ms

 2 1:1:1::1 3 ms 2 ms 2 ms

           We can see RTD choose route from RTB.

    After apply policy, we can see result below：

    <RTD-3020>tracert ipv6 1:1:1::1

 traceroute to 1:1:1::1 30 hops max,60 bytes packet, press CTRL_C to break

       1 4::1 2 ms 2 ms 2 ms

       2 1:1:1::1 3 ms 3 ms 2 ms

We can see RTD choose route from RTC, the reason is different MED value.Further more, we can check MED value by display bgp ipv6 routing-table .