GoBGP Practical Activity

Task description

You have the following topology:

GoBGP is installed and peering is configured. Configure BGP policies to ensure that link "A" has higher preference than link "B" and traffic between rt1 and rt3 passed through rt2 router.

1. Setup Vagrant

Download from https://www.vagrantup.com/downloads.html and install

2. Pull repository

git clone https://github.com/Astrarog/hse-gobgp-bgp

3. Setup environment

cd hse-gobgp-bgp
vagrant up

4. How virtual routers was configured

4.1 Splitting neighbours set

+-----+ | rt1 | +-----+	+-----+ | rt2 | +-----+	+-----+ | rt3 | +-----+
# Neighbors to announce Prefixes [[defined-sets.neighbor-sets]] neighbor-set-name = "rt2-la" neighbor-info-list = ["10.20.0.20"] [[defined-sets.neighbor-sets]] neighbor-set-name = "rt2-rt3-lb" neighbor-info-list = ["10.10.0.20", "10.10.0.30"]	# Neighbors to announce Prefixes [[defined-sets.neighbor-sets]] neighbor-set-name = "rt1-lb" neighbor-info-list = ["10.10.0.20"] [[defined-sets.neighbor-sets]] neighbor-set-name = "rt1-la-rt3-lb" neighbor-info-list = ["10.20.0.10", "10.10.0.30"]	# Neighbors to announce Prefixes [[defined-sets.neighbor-sets]] neighbor-set-name = "all-neighbors-no-rt1" neighbor-info-list = ["10.10.0.20"] [[defined-sets.neighbor-sets]] neighbor-set-name = "rt1" neighbor-info-list = ["10.10.0.10"]

4.2 Creating new export policies

+-----+ | rt1 | +-----+	+-----+ | rt2 | +-----+	+-----+ | rt3 | +-----+
# Export Policy [[policy-definitions]] name = "export-policy" [[policy-definitions.statements]] name = "export-local-net-to-la" [policy-definitions.statements.conditions.match-prefix-set] prefix-set = "local-net" [policy-definitions.statements.conditions.match-neighbor-set] neighbor-set = "rt2-la" [policy-definitions.statements.actions] route-disposition = "accept-route" [[policy-definitions.statements]] name = "export-local-net-to-lb" [policy-definitions.statements.conditions.match-prefix-set] prefix-set = "local-net" [policy-definitions.statements.conditions.match-neighbor-set] neighbor-set = "rt2-rt3-lb" [policy-definitions.statements.actions] route-disposition = "accept-route" [policy-definitions.statements.actions.bgp-actions] [policy-definitions.statements.actions.bgp-actions.set-as-path-prepend] as = "65010" repeat-n = 3	# Prefixes to announce [[defined-sets.prefix-sets]] prefix-set-name = "local-net" [[defined-sets.prefix-sets.prefix-list]] ip-prefix = "172.20.20.0/24" masklength-range = "24..24" [[defined-sets.prefix-sets]] prefix-set-name = "all-net" [[defined-sets.prefix-sets.prefix-list]] ip-prefix = "172.20.0.0/16" masklength-range = "24..24" # Export Policy [[policy-definitions]] name = "export-policy" [[policy-definitions.statements]] name = "export-local-net" [policy-definitions.statements.conditions.match-prefix-set] prefix-set = "local-net" [policy-definitions.statements.conditions.match-neighbor-set] neighbor-set = "rt1-lb" [policy-definitions.statements.actions] route-disposition = "accept-route" [[policy-definitions.statements]] name = "export-all" [policy-definitions.statements.conditions.match-prefix-set] prefix-set = "all-net" [policy-definitions.statements.conditions.match-neighbor-set] neighbor-set = "rt1-la-rt3-lb" [policy-definitions.statements.actions] route-disposition = "accept-route"	# Export Policy [[policy-definitions]] name = "export-policy" [[policy-definitions.statements]] name = "export-local-net-no-rt1" [policy-definitions.statements.conditions.match-prefix-set] prefix-set = "local-net" [policy-definitions.statements.conditions.match-neighbor-set] neighbor-set = "all-neighbors-no-rt1" [policy-definitions.statements.actions] route-disposition = "accept-route" [[policy-definitions.statements]] name = "export-local-net-to-rt1" [policy-definitions.statements.conditions.match-prefix-set] prefix-set = "local-net" [policy-definitions.statements.conditions.match-neighbor-set] neighbor-set = "rt1" [policy-definitions.statements.actions] route-disposition = "accept-route" [policy-definitions.statements.actions.bgp-actions] [policy-definitions.statements.actions.bgp-actions.set-as-path-prepend] as = "65030" repeat-n = 3

5. Validate with traceroute

+-----+ +-----+ +-----+ | rt1 |---> --->| rt2 |---> --->| rt3 | +-----+ +-----+ +-----+	+-----+ +-----+ +-----+ | rt3 |---> --->| rt2 |---> --->| rt1 | +-----+ +-----+ +-----+

6. Destroy VM

vagrant destroy