Vyatta Network OS Documentation

Learn how to install, configure and operate the Vyatta NOS, which helps drive our virtual networking & physical platforms portfolio.

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Synchronization

Basic synchronization configuration

To enable traffic to be routed through multiple asynchronous systems (AS), IGP must propagate iBGP routes within its AS before they advertise them to peers outside its AS. All routers in an AS must learn of a route before BGP advertises the route outside of the AS. A BGP router must have synchronization disabled (the default setting) to validate these routes and install them into its routing table.

In this section, you configure BGP synchronization on the routers labeled BGP17,L BGP18, BPG19, BGP20, and BGP21 in the reference network diagram. The routers are advertising their routes on networks 10.0.40.0/24 and 10.0.50.0/24.

This section presents a sample configuration for BGP synchronization. The configuration example is based on the reference diagram in the following figure.

Figure 1. BGP synchronization topology

BGP synchronization must have AS200 configured as a transit between AS100 and AS300, and AS200 must have all routers meshed through iBGP.

BGP17 advertises a route to BGP18 through eBGP and the route is forwarded using iBGP to BGP20 through BGP19. For BGP20 to forward the route outside its AS to BGP 21, BGP19 must add the network in its routing table or the packet be dropped. BGP synchronization enables BGP19 to learn the network and to notify BGP20, before allowing BGP20 to forward the route to BGP21.

To create a basic BGP synchronization configuration, perform the steps in the following table:

Table 1. Basic BGP synchronization configuration

Router

Step

Commands

BGP17

Configure interfaces.

vyatta@BGP17# set interfaces dataplane dp0p160p1 address 10.1.34.133/24
vyatta@BGP17# set interfaces dataplane dp0p192p1 address 20.1.1.2/24
vyatta@BGP17# set interfaces dataplane dp0p224p1 address 100.1.1.1/24
vyatta@BGP17# set interfaces loopback lo

BGP17

Establish BGP, by configuring BGP neighbors.

vyatta@BGP17# set protocols bgp 100 neighbor 20.1.1.1 ebgp-multihop 1
vyatta@BGP17# set protocols bgp 100 neighbor 20.1.1.1 remote-as 200

BGP17

Advertise the route to establish the BGP route as the next hop and reachable. The eBGP route becomes an iBGP route.

vyatta@BGP17# set protocols bgp 100 network 100.1.1.0/24
vyatta@BGP17# set protocols ospf area 0.0.0.0 network 20.1.1.0/24

BGP18

Configure interfaces.

vyatta@BGP18# set interfaces dataplane dp0p160p1 address 10.1.34.134/24
vyatta@BGP18# set interfaces dataplane dp0p192p1 address 20.1.1.1/24
vyatta@BGP18# set interfaces dataplane dp0p224p1 address 30.1.1.1/24
vyatta@BGP18# set interfaces loopback lo address 175.18.18.18/32

BGP18

Establish BGP, by configuring BGP neighbors.

vyatta@BGP18# set protocols bgp 200 neighbor 20.1.1.2 ebgp-multihop 1
vyatta@BGP18# set protocols bgp 200 neighbor 20.1.1.2 remote-as 100
vyatta@BGP18# set protocols bgp 200 neighbor 175.20.20.20 remote-as 200
vyatta@BGP18# set protocols bgp 200 neighbor 175.20.20.20 update-source 175.18.18.18

BGP18

Advertise the route to establish the BGP route as the next hop and reachable. The eBGP route becomes an iBGP route.

vyatta@BGP18# set protocols bgp 200 parameters
vyatta@BGP18# set protocols ospf area 0.0.0.0 network 20.1.1.0/24
vyatta@BGP18# set protocols ospf area 0.0.0.0 network 30.1.1.0/24
vyatta@BGP18# set protocols ospf area 0.0.0.0 network 175.18.18.18/32
vyatta@BGP18# set protocols ospf redistribute bgp

BGP19

Configure interfaces.

vyatta@BGP19# set interfaces dataplane dp0p160p1 address 10.1.34.135/24
vyatta@BGP19# set interfaces dataplane dp0p192p1 address 30.1.1.2/24
vyatta@BGP19# set interfaces dataplane dp0p224p1 address 40.1.1.2/24
vyatta@BGP19# set interfaces loopback lo

BGP19

Advertise the route to establish the BGP route as the next hop and reachable. The eBGP route becomes an iBGP route.

vyatta@BGP19# set protocols ospf area 0.0.0.0 network 20.1.1.0/24
vyatta@BGP19# set protocols ospf area 0.0.0.0 network 30.1.1.0/24
vyatta@BGP19# set protocols ospf area 0.0.0.0 network 40.1.1.0/24

BGP20

Configure Interfaces

vyatta@BGP20# set interfaces dataplane dp0p160p1 address 10.1.34.136/24
vyatta@BGP20# set interfaces dataplane dp0p192p1 address 40.1.1.1/24
vyatta@BGP20# set interfaces dataplane dp0p224p1 address 50.1.1.1/24
vyatta@BGP20# set interfaces loopback lo address 175.20.20.20/32

BGP20

Establish BGP, by configuring BGP neighbors.

vyatta@BGP20# set protocols bgp 200 neighbor 50.1.1.2 ebgp-multihop 1
vyatta@BGP20# set protocols bgp 200 neighbor 50.1.1.2 remote-as 300
vyatta@BGP20# set protocols bgp 200 neighbor 175.18.18.18 remote-as 200
vyatta@BGP20# set protocols bgp 200 neighbor 175.18.18.18 soft-reconfiguration inbound
vyatta@BGP20# set protocols bgp 200 neighbor 175.18.18.18 update-source 175.20.20.20

BGP20

Configure synchronization and advertise the route to establish the BGP route as the next hop and reachable. The eBGP route becomes an iBGP route.

vyatta@BGP20# set protocols bgp 200 parameters synchronization
vyatta@BGP20# set protocols ospf area 0.0.0.0 network 40.1.1.0/24
vyatta@BGP20# set protocols ospf area 0.0.0.0 network 50.1.1.0/24
vyatta@BGP20# set protocols ospf area 0.0.0.0 network 175.20.20.20/32

BGP21

Configure Interfaces

vyatta@BGP21# set interfaces dataplane dp0p160p1 address 10.1.34.137/24
vyatta@BGP21#set interfaces dataplane dp0p192p1 address 50.1.1.2/24
vyatta@BGP21# set interfaces loopback lo address 175.21.21.21/32

BGP21

Establish BGP, by configuring BGP neighbors.

vyatta@BGP21# set protocols bgp 300 neighbor 50.1.1.1 ebgp-multihop 1
vyatta@BGP21# set protocols bgp 300 neighbor 50.1.1.1 remote-as 200
vyatta@BGP21# set protocols bgp 300 neighbor 50.1.1.1 soft-reconfiguration inbound

BGP21

Advertise the route to establish the BGP route as the next hop and reachable. The eBGP route becomes an iBGP route.

vyatta@BGP21#set protocols ospf area 0.0.0.0 network 50.1.1.0/24
vyatta@BGP21# set protocols ospf area 0.0.0.0 network 175.21.21.21/32

Verifying the configuration

To display routes and their status for BGP 17, enter the command in the following example:

vyatta@BGP17# show ip route
Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
       O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
       > - selected route, * - FIB route, p - stale info

S    *> 10.0.0.0/8 [1/0] via 10.1.34.1, dp0p160p1
C    *> 10.1.34.0/24 is directly connected, dp0p160p1
O       20.1.1.0/24 [110/10] is directly connected, dp0p192p1, 15:39:00
C    *> 20.1.1.0/24 is directly connected, dp0p192p1
O    *> 30.1.1.0/24 [110/20] via 20.1.1.1, dp0p192p1, 00:26:54
O    *> 40.1.1.0/24 [110/30] via 20.1.1.1, dp0p192p1, 00:26:54
O    *> 50.1.1.0/24 [110/40] via 20.1.1.1, dp0p192p1, 00:26:54
C    *> 100.1.1.0/24 is directly connected, dp0p224p1
C    *> 127.0.0.0/8 is directly connected, lo
O    *> 175.18.18.18/32 [110/20] via 20.1.1.1, dp0p192p1, 00:26:54
O    *> 175.20.20.20/32 [110/40] via 20.1.1.1, dp0p192p1, 00:26:54
O    *> 175.21.21.21/32 [110/50] via 20.1.1.1, dp0p192p1, 00:26:54

To verify the network, next hop routes, and their status in the BGP synchronization configuration, enter the command in the following example:

vyatta@BGP17# show ip bgp neigh 20.1.1.1 advertised-routes
BGP table version is 2, local router ID is 100.1.1.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 100.1.1.0/24     20.1.1.2                      100  32768 i

Total number of prefixes 1

To display the routes and their status for BGP 18, enter the command in the following example:

vyatta@BGP18# show ip route
Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
> - selected route, * - FIB route, p - stale info
S *> 10.0.0.0/8 [1/0] via 10.1.34.1, dp0p160p1
C *> 10.1.34.0/24 is directly connected, dp0p160p1
O 20.1.1.0/24 [110/10] is directly connected, dp0p192p1, 1d00h18m
C *> 20.1.1.0/24 is directly connected, dp0p192p1
O 30.1.1.0/24 [110/10] is directly connected, dp0p224p1, 21:20:09
C *> 30.1.1.0/24 is directly connected, dp0p224p1
O *> 40.1.1.0/24 [110/20] via 30.1.1.2, dp0p224p1, 16:28:46
O *> 50.1.1.0/24 [110/30] via 30.1.1.2, dp0p224p1, 00:50:46
B *> 100.1.1.0/24 [20/0] via 20.1.1.2, dp0p192p1, 00:28:08
C *> 127.0.0.0/8 is directly connected, lo
C *> 175.18.18.18/32 is directly connected, lo
O *> 175.20.20.20/32 [110/30] via 30.1.1.2, dp0p224p1, 00:40:19
O *> 175.21.21.21/32 [110/40] via 30.1.1.2, dp0p224p1, 00:44:16

To display advertised routes for BGP 18, enter the command in the following example:

vyatta@BGP18# show ip bgp neigh 175.20.20.20 advertised-routes

BGP table version is 3, local router ID is 175.18.18.18
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*>i100.1.1.0/24     20.1.1.2                      100      0 100 i

Total number of prefixes 1

To display ospf updates for BGP 18, enter the command in the following example:

vyatta@BGP18# show ip ospf data

OSPF Router with ID (20.1.1.1) (Process ID 0)

                Router Link States (Area 0.0.0.0)

Link ID         ADV Router      Age  Seq#       CkSum  Link count
20.1.1.1        20.1.1.1        1338 0x80000180 0xc944 3
20.1.1.2        20.1.1.2        1740 0x80000172 0x4e29 1
30.1.1.2        30.1.1.2        1584 0x80000030 0x6ab7 2
40.1.1.1        40.1.1.1         656 0x8000002a 0x2bbe 3
50.1.1.2        50.1.1.2         906 0x80000007 0x86db 2

                Net Link States (Area 0.0.0.0)

Link ID         ADV Router      Age  Seq#       CkSum
20.1.1.2        20.1.1.2        1736 0x80000007 0x2bc9
30.1.1.2        30.1.1.2         964 0x80000027 0x5462
40.1.1.1        40.1.1.1        1036 0x80000002 0x8a2b
50.1.1.2        50.1.1.2        1466 0x80000002 0x4e3d

                AS External Link States

Link ID         ADV Router      Age  Seq#       CkSum  Route              Tag
100.1.1.0       20.1.1.1        1337 0x80000001 0x0537 E2 100.1.1.0/24    0

To display routes and their status for BGP 19, enter command in the following example:

vyatta@BGP19# run show ip route
Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
       O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
       > - selected route, * - FIB route, p - stale info

S    *> 10.0.0.0/8 [1/0] via 10.1.34.1, dp0p160p1
C    *> 10.1.34.0/24 is directly connected, dp0p160p1
O    *> 20.1.1.0/24 [110/20] via 30.1.1.1, dp0p192p1, 15:18:49
O       30.1.1.0/24 [110/10] is directly connected, dp0p192p1, 20:58:07
C    *> 30.1.1.0/24 is directly connected, dp0p192p1
O       40.1.1.0/24 [110/10] is directly connected, dp0p224p1, 16:08:04
C    *> 40.1.1.0/24 is directly connected, dp0p224p1
O    *> 50.1.1.0/24 [110/20] via 40.1.1.1, dp0p224p1, 00:30:04
O E2 *> 100.1.1.0/24 [110/1] via 30.1.1.1, dp0p192p1, 00:00:05
C    *> 127.0.0.0/8 is directly connected, lo
O    *> 175.18.18.18/32 [110/20] via 30.1.1.1, dp0p192p1, 00:25:26
O    *> 175.20.20.20/32 [110/20] via 40.1.1.1, dp0p224p1, 00:19:36
O    *> 175.21.21.21/32 [110/30] via 40.1.1.1, dp0p224p1, 00:23:34

To display advertised routes for BGP 20, enter the command in the following example:

vyatta@BGP20# show ip bgp neigh 50.1.1.2 advertised-routes

BGP table version is 6, local router ID is 175.20.20.20
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 100.1.1.0/24     50.1.1.1                      100      0 100 i

Total number of prefixes 1

To display routes and their status for BGP 20, enter the command in the following example:

vyatta@BGP20# run show ip route
Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
       O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
       > - selected route, * - FIB route, p - stale info

S    *> 10.0.0.0/8 [1/0] via 10.1.34.1, dp0p160p1
C    *> 10.1.34.0/24 is directly connected, dp0p160p1
O    *> 20.1.1.0/24 [110/30] via 40.1.1.2, dp0p192p1, 01:00:23
O    *> 30.1.1.0/24 [110/20] via 40.1.1.2, dp0p192p1, 01:00:23
O       40.1.1.0/24 [110/10] is directly connected, dp0p192p1, 16:34:02
C    *> 40.1.1.0/24 is directly connected, dp0p192p1
O       50.1.1.0/24 [110/10] is directly connected, dp0p224p1, 00:56:19
C    *> 50.1.1.0/24 is directly connected, dp0p224p1
O E2 *> 100.1.1.0/24 [110/1] via 40.1.1.2, dp0p192p1, 00:26:20
B       100.1.1.0/24 [200/0] via 20.1.1.2 (recursive via 40.1.1.2 ), 00:26:44
C    *> 127.0.0.0/8 is directly connected, lo
O    *> 175.18.18.18/32 [110/30] via 40.1.1.2, dp0p192p1, 00:51:41
C    *> 175.20.20.20/32 is directly connected, lo
O    *> 175.21.21.21/32 [110/20] via 50.1.1.2, dp0p224p1, 00:49:48

To verify the network, next hop routes, and their status in the BGP synchronization configuration, enter the command in the following example:

vyatta@BGP20# show ip bgp
BGP table version is 6, local router ID is 175.20.20.20
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal, l - labeled
              S Stale
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*>i100.1.1.0/24     20.1.1.2                 0    100      0 100 i

Total number of prefixes 1

To display received routes for BGP 21, enter the command in the following example:

vyatta@BGP21# show ip bgp neigh 50.1.1.1 received-routes
BGP table version is 8, local router ID is 175.21.21.21
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal
Origin codes: i - IGP, e - EGP, ? - incomplete

   Network          Next Hop            Metric LocPrf Weight Path
*> 100.1.1.0/24     50.1.1.1                               0 200 100 i

Total number of prefixes 1

To display routes and their status for BGP 21, enter the command in the following example:

vyatta@BGP21# show ip routes
Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
       O - OSPF, IA - OSPF inter area
       N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
       E1 - OSPF external type 1, E2 - OSPF external type 2
       i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
       > - selected route, * - FIB route, p - stale info

S    *> 10.0.0.0/8 [1/0] via 10.1.34.1, dp0p160p1
C    *> 10.1.34.0/24 is directly connected, dp0p160p1
O    *> 20.1.1.0/24 [110/40] via 50.1.1.1, dp0p192p1, 00:55:30
O    *> 30.1.1.0/24 [110/30] via 50.1.1.1, dp0p192p1, 00:55:30
O    *> 40.1.1.0/24 [110/20] via 50.1.1.1, dp0p192p1, 00:55:30
O       50.1.1.0/24 [110/10] is directly connected, dp0p192p1, 00:56:54
C    *> 50.1.1.0/24 is directly connected, dp0p192p1
O E2    100.1.1.0/24 [110/1] via 50.1.1.1, dp0p192p1, 00:28:38
B    *> 100.1.1.0/24 [20/0] via 50.1.1.1, dp0p192p1, 00:28:47
C    *> 127.0.0.0/8 is directly connected, lo
O    *> 175.18.18.18/32 [110/40] via 50.1.1.1, dp0p192p1, 00:54:00
O    *> 175.20.20.20/32 [110/20] via 50.1.1.1, dp0p192p1, 00:48:10
C    *> 175.21.21.21/32 is directly connected, lo