Border Gateway Protocol ( BGP Confederation ) on Mikrotik

Border Gateway Protocol ( BGP Confederation ) on Mikrotik

z

7:02 PM

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Otodidak learner - Previously we have learned about the route reflector which we can use to solve problems on the IBGP full mesh topology Peering. in this Post, we will learn BGP Confederation.
BGP Confederation also we can utilize to overcome the problem of full mesh IBGP peering at, only use a slightly different method to route reflector. BGP Confederation will create a sub-AS on each router IBGP. for more details see the topology that I include.

First we configure the IP address on all routers

[admin@MikroTik] > system identity set name=R1 [admin@R1] > interface bridge add name=lo0 [admin@R1] > ip address [admin@R1] /ip address> add address=22.22.22.1/24 interface=ether1 [admin@R1] /ip address> add address=12.12.12.1/24 interface=ether2 [admin@R1] /ip address> add address=192.168.0.1/24 interface=lo0

[admin@MikroTik] > system identity set name=R2 [admin@R2] > interface bridge add name=lo0 [admin@R2] > ip address [admin@R2] /ip address> add address=22.22.22.2/24 interface=ether1 [admin@R2] /ip address> add address=33.33.33.2/24 interface=ether2 [admin@R2] /ip address> add address=192.168.1.1/24 interface=lo0

[admin@MikroTik] > system identity set name=R3 [admin@R3] > interface bridge add name=lo0 [admin@R3] > ip address [admin@R3] /ip address> add address=33.33.33.3/24 interface=ether1 [admin@R3] /ip address> add address=12.12.12.3/24 interface=ether2 [admin@R3] /ip address> add address=192.168.2.1/24 interface=lo0

we have finished to configure BGP confederation.

Border Gateway Protocol ( Route Reflector ) On Mikrotik

Border Gateway Protocol ( Route Reflector ) On Mikrotik

z

6:24 PM

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Border Gateway Protocol ( Route Reflector ) On Mikrotik

Almost same with Border Gateway Protocol ( BGP Backdoor )  then we have to configure Full Mesh Peering. It certainly would be a problem if we have 100 IBGP router, full mesh peering network would be very burdensome.

To overcome these problems, we can configure the route reflector, so that each router IBGP only need to do peering with the route reflector. The following topology which we will use


First, we configure the IP address of the entire router

[admin@MikroTik] > system identity set name=R1

[admin@R1] > interface bridge add name=lo0
[admin@R1] > ip address
[admin@R1] /ip address> add address=22.22.22.1/24 interface=ether1
[admin@R1] /ip address> add address=192.168.0.1/24 interface=lo0

[admin@MikroTik] > system identity set name=R2
[admin@R2] > interface bridge add name=lo0
[admin@R2] > ip address
[admin@R2] /ip address> add address=22.22.22.2/24 interface=ether1
[admin@R2] /ip address> add address=23.23.23.2/24 interface=ether2
[admin@R2] /ip address> add address=192.168.1.1/24 interface=lo0

[admin@MikroTik] > system identity set name=R3
[admin@R3] > interface bridge add name=lo0
[admin@R3] > ip address
[admin@R3] /ip address> add address=23.23.23.3/24 interface=ether1
[admin@R3] /ip address> add address=192.168.3.1/24 interface=lo0

Next we try to create IBGP peering at R1, R2, and R3,

[admin@R1] /ip address> /routing bgp
[admin@R1] /routing bgp> instance set 0 as=123
[admin@R1] /routing bgp> peer add remote-address=22.22.22.2 remote-as=123
[admin@R1] /routing bgp> network add network=192.168.0.0/24

[admin@R2] /ip address> /routing bgp
[admin@R2] /routing bgp> instance set 0 as=123
[admin@R2] /routing bgp> peer add remote-address=22.22.22.1 remote-as=123 route-reflect=yes
[admin@R2] /routing bgp> peer add remote-address=23.23.23.3 remote-as=123 route-reflect=yes
[admin@R2] /routing bgp> network add network=192.168.1.0/24

[admin@R3] /ip address> /routing bgp
[admin@R3] /routing bgp> instance set 0 as=123
[admin@R3] /routing bgp> peer add remote-address=23.23.23.2 remote-as=123
[admin@R3] /routing bgp> network add network=192.168.2.0/24

Note that we configure the router R2 as a reflector (parameter route-reflect = yes). next to the test, we look at the routing table on R1

[admin@R1] /routing bgp> /ip route print

Flags: X - disabled, A - active, D - dynamic,
C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme,
B - blackhole, U - unreachable, P - prohibit
# DST-ADDRESS PREF-SRC GATEWAY DISTANCE
0 ADC 22.22.22.0/24 22.22.22.1 ether1 0
1 A S 23.23.23.0/24 22.22.22.2 1
2 ADC 192.168.0.0/24 192.168.0.1 lo0 0
3 ADb 192.168.1.0/24 22.22.22.2 200
4 ADb 192.168.3.0/24 23.23.23.3 200

Border Gateway Protocol ( BGP Backdoor )

Border Gateway Protocol ( BGP Backdoor )

z

5:51 PM

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After we learned , External Border Gateway Protocol (EBGP Peering Physical Interface) On Mikrotik We will learn about BGP Backdoor. BGP Backdoor is a technique for manipulating the selection between best path routing protocol EBGP with IGP routing protocols such as OSPF, EIGRP, etc.

Border Gateway Protocol ( BGP Backdoor )

By default, the value of AD EBGP is 20, EBGP certainly would be an advantage compared with IGP protocols such as OSPF, EIGRP, etc.. With BGP Backdoor, we can manipulate so IGP routing protocol takes precedence over EBGP

We will configure BGP Peering between R1 to R3 and R2 to R3. While the link between R1 and R2, we will only configure OSPF

R1(config)#int e0/0

R1(config-if)#no sh R1(config-if)#ip add 12.12.12.1 255.255.255.0
R1(config-if)#int e0/1 R1(config-if)#no sh
R1(config-if)#ip add 13.13.13.1 255.255.255.0
R1(config-if)#int l0 R1(config-if)#ip add 1.1.1.1 255.255.255.255
R1(config-if)#router bgp 1
R1(config-router)#nei 13.13.13.3 remote-as 3
R1(config-router)#net 1.1.1.1 mask 255.255.255.255
R1(config-router)#router ospf 1
R1(config-router)#net 12.12.12.0 0.0.0.255 are 0
R1(config-router)#net 1.1.1.1 0.0.0.0 are 0

R2(config)#int e0/0
R2(config-if)#no sh
R2(config-if)#ip add 12.12.12.2 255.255.255.0
R2(config-if)#int e0/1 R2(config-if)#no sh
R2(config-if)#ip add 23.23.23.2 255.255.255.0
R2(config-if)#router bgp 2
R2(config-router)#nei 23.23.23.3 remote-as 3
R2(config-router)#router ospf 1
R2(config-router)#net 12.12.12.0 0.0.0.255 are 0

R3(config)#int e0/0
R3(config-if)#no sh
R3(config-if)#ip add 13.13.13.3 255.255.255.0
R3(config-if)#int e0/1 R3(config-if)#no sh
R3(config-if)#ip add 23.23.23.3 255.255.255.0
R3(config-if)#router bgp 3
R3(config-router)#nei 13.13.13.1 remote-as 1
R3(config-router)#nei 23.23.23.2 rempte-as 2

Now we check the routing table on R2

R2(config-router)#do sh ip ro
1.0.0.0/32 is subnetted, 1 subnets
B 1.1.1.1 [20/0] via 23.23.23.3, 00:06:15
12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 12.12.12.0/24 is directly connected, Ethernet0/0
23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 23.23.23.0/24 is directly connected, Ethernet0/1

[Note]: R2 prefer to use EBGP routing protocol to heading 1.1.1.1 than OSPF. And if using BGP, R2 R3 must pass first. Whereas if you use OSPF, should R2 can go straight to R1. Why R2 can choose BGP than OSPF ?? because the value of AD BGP is 20 while the value of OSPF is 110 AD.
In order R2 prefer use OSPF routing protocol, we can configure BGP Backdoor

R2(config)#router bgp 2

R2(config-router)#net 1.1.1.1 mask 255.255.255.255 backdoor

Now we check the routing table on R2

R2(config-router)#do sh ip ro
1.0.0.0/32 is subnetted, 1 subnets
O 1.1.1.1 [110/11] via 12.12.12.1, 00:00:06, Ethernet0/0
12.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C
12.12.12.0/24 is directly connected, Ethernet0/0
23.0.0.0/8 is variably subnetted, 2 subnets, 2 masks C
23.23.23.0/24 is directly connected, Ethernet0/1

Note that at this time has chosen R2 using OSPF routing protocol BGP compared to heading 1.1.1.1

External Border Gateway Protocol (EBGP Peering Physical Interface) On Mikrotik

External Border Gateway Protocol (EBGP Peering Physical Interface) On Mikrotik

z

8:30 PM

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We have learned  EBGP Loopback On Mikrotik

  Peering EBGP  when there are two or more routers that have different AS Number. The following topology which we will use. First, configure the IP address on R1 and R2 based topology above

[admin@MikroTik] > system identity set name=R1
[admin@R1] > interface bridge add name=lo0
[admin@R1] > ip address
[admin@R1] /ip address>add address=22.22.22.1/24 interface=ether1
[admin@R1] /ip address> add address=192.168.0.1/24 interface=lo0

and

[admin@MikroTik] > system identity set name=R2
[admin@R2] > interface bridge add name=lo0
[admin@R2] > ip address
[admin@R2] /ip address> add address=22.22.22.2/24 interface=ether1
[admin@R2] /ip address> add address=192.168.1.1/24 interface=lo0

Next, We Peering BGP configuration on R1 and R2
[admin@R1] > routing bgp [admin@R1] /routing bgp> instance set 0 as=100 [admin@R1] /routing bgp> peer add remote-address=22.22.22.2 remote-as=200 [admin@R1] /routing bgp> network add network=192.168.0.0/24

and

[admin@R2] > routing bgp [admin@R2] /routing bgp> instance set 0 as=200 [admin@R2] /routing bgp> peer add remote-address=22.22.22.1 remote-as=100 [admin@R2] /routing bgp> network add network=192.168.1.0/24


For testing we look at the routing table on R1, R1 sure to recognize the 192.168.1.0/24 network through BGP.

[admin@R1] /routing bgp> /ip route print Flags: X - disabled, A - active, D - dynamic, C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme, B - blackhole, U - unreachable, P - prohibit # DST-ADDRESS PREF-SRC GATEWAY DISTANCE 0 ADC 22.22.22.1/24 22.22.22.1 ether1 0 1 ADC 192.168.0.0/24 192.168.0.1 lo0 0 2 ADb 192.168.2.0/24 22.22.22.2 20

EBGP Peering (Loopback Interface) On Mikrotik

EBGP Peering (Loopback Interface) On Mikrotik

z

11:56 PM

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We learn EBGP peering using a loopback interface on the proxy. For
the same reason IBGP peering using a loopback interface that we

discussed earlier. That is because the loopback interface will never be down as long as at least one active interface on the router.
For The First First, we configure the IP address on both routers according to the topology.

[admin@MikroTik] > system identity set name=R1
[admin@R1] > interface bridge add name=lo0 [admin@R1] > ip address
[admin@R1] /ip address> add address=12.12.12.1/24 interface=ether1
[admin@R1] /ip address> add address=192.168.1.1/24 interface=lo0

[admin@MikroTik] > system identity set name=R2
[admin@R2] > interface bridge add name=lo0
[admin@R2] > ip address
[admin@R2] /ip address> add address=12.12.12.2/24 interface=ether1
[admin@R2] /ip address> add address=192.168.2.1/24 interface=lo0

Before configuring EBGP peering using a loopback interface, we must introduce IP Loopback R1 to R2, and vice versa. We can use static routing or dynamic routing (OSPF).

[admin@MikroTik] > system identity set name=R2
[admin@R2] > interface bridge add name=lo0
[admin@R2] > ip address
[admin@R2] /ip address> add address=12.12.12.2/24 interface=ether1
[admin@R2] /ip address> add address=192.168.2.1/24 interface=lo0

we need to configure the multihop on R1. This is because the IP Address Loopback R2 is not considered to be directly connected By R1, as well as the R2. For testing, we look at the routing table on R1

[admin@R1] /routing bgp> /ip route print
Flags: X - disabled, A - active, D - dynamic,
C - connect, S - static, r - rip, b - bgp, o - ospf, m - mme,
B - blackhole, U - unreachable, P - prohibit
# DST-ADDRESS PREF-SRC GATEWAY DISTANCE
0 ADC 12.12.12.0/24 12.12.12.1 ether1 0
1 ADC 192.168.1.0/24 192.168.1.1 lo0 0
2 A S 192.168.2.0/24 12.12.12.2 1
3 Db 192.168.2.0/24 192.168.2.1 20