BGP Large Communities playground

What BGP Large Communities are

A good site already explains it very well: http://largebgpcommunities.net/

This playground

Luckly many vendors and networking software authors are approaching this solution and started implementing the draft. This repository (presumptuously) wants to offer some hints to quickly have a bgp-large-communities-aware lab up & running on the basis of the latest code available.

Currently it supports the following products:

• ExaBGP
• GoBGP
• BIRD
• pmacct
• Quagga

Docker images have been built in order to have them running on the latest BGP-Large-Communities-aware code fetched from the master branch of them.

Disclaimer

These images have been created with the only purpose of being used in a "playground", for labs and interoperability tests. They do not implement any security best practice. Use them at your own risk.

Tests

I used this Playground to run some interoperability tests and to verify implemented features among the covered tools: here are my findings.

How to run it

# git clone https://github.com/pierky/bgp-large-communities-playground.git
# cd bgp-large-communities-playground/
# docker network create --subnet=192.0.2.0/24 bgp-large-communities-playground
# docker run --net bgp-large-communities-playground --ip 192.0.2.2 --hostname=exabgp -d -v `pwd`/exabgp:/etc/exabgp:rw pierky/exabgp
# docker run --net bgp-large-communities-playground --ip 192.0.2.3 --hostname=gobgp -d -v `pwd`/gobgp:/etc/gobgp:rw pierky/gobgp
# docker run --net bgp-large-communities-playground --ip 192.0.2.4 --hostname=bird -d -v `pwd`/bird:/etc/bird:rw pierky/bird
# docker run --net bgp-large-communities-playground --ip 192.0.2.5 --hostname=pmacct -d -v `pwd`/pmacct:/etc/pmacct:rw pierky/pmacct
# docker run --net bgp-large-communities-playground --ip 192.0.2.6 --hostname=quagga -d -v `pwd`/quagga:/etc/quagga:rw pierky/quagga

This is enough to create a virtual network, have ExaBGP running on 192.0.2.2, GoBGP on 192.0.2.3, BIRD on 192.0.2.4 and Quagga on 192.0.2.6. The startup config files (exabgp/exabgp.conf, gobgp/gobgp.conf, bird/bird.conf and quagga/quagga.conf) allow these instances to establish BGP sessions:

# cat exabgp/log
...
Thu, 14 Sep 2016 17:54:57 5      network       Connected to peer neighbor 192.0.2.3 local-ip 192.0.2.2 local-as 65536 peer-as 65537 router-id 192.0.2.2 family

# cat gobgp/log
...
time="2016-09-14T17:54:57Z" level=info msg="Peer Up" Key=192.0.2.2 State="BGP_FSM_OPENCONFIRM" Topic=Peer
time="2016-09-14T17:54:57Z" level=info msg="Peer Up" Key=192.0.2.4 State="BGP_FSM_OPENCONFIRM" Topic=Peer

The BGP daemon built into pmacct is started too: ExaBGP is configured to setup a neighborship with it and to announce some prefixes:

# cat pmacct/log
...
INFO ( default/core/BGP ): [192.0.2.2] BGP peers usage: 1/2
INFO ( default/core/BGP ): [192.0.2.2] Capability: MultiProtocol [1] AFI [1] SAFI [1]

INFO ( default/core/BGP ): [192.0.2.2] Capability: 4-bytes AS [41] ASN [65536]
INFO ( default/core/BGP ): [192.0.2.2] BGP_OPEN: Asn: 65536 HoldTime: 180

# cat pmacct/bgp.log
{"event_type": "dump_init", "dump_period": 60}
{"event_type": "dump", "ip_prefix": "192.0.2.2/32", ..., "lcomms": "65536:1:1", ...}
{"event_type": "dump", "ip_prefix": "192.0.2.3/32", ..., "lcomms": "65537:1:1", ...}
{"event_type": "dump", "ip_prefix": "192.0.2.4/32", ..., "lcomms": "65538:1:1", ...}
{"event_type": "dump_close", "entries": 3, "tables": 1}

Commands can be run on the instances interactively, by attaching a new terminal to the Docker container, or directly from the host:

# # take note of the container ID of each instance
# docker ps
CONTAINER ID        IMAGE               ...
ff5c323d2118        pierky/gobgp        ...
2c46decfb88a        pierky/exabgp       ...
...

# docker exec -it ff5c323d2118 bash
root@gpbgp:/go# gobgp neighbor
Peer         AS  Up/Down State       |#Advertised Received Accepted
192.0.2.2 65536 00:02:19 Establ      |          0        1        1
192.0.2.4 65538 00:01:57 Establ      |          1        1        1
root@gpbgp:/go# exit
exit

# docker exec -it ff5c323d2118 gobgp global
AS:        65537
Router-ID: 192.0.2.3
Listening Port: 179, Addresses: 0.0.0.0, ::
MPLS Label Range: 16000..1048575

Since ExaBGP's config file contains a static route which is tagged with a BGP Large Community we can verify how GoBGP and BIRD see it:

# docker exec ff5c323d2118 gobgp neighbor 192.0.2.2 adj-in
    Network             Next Hop             AS_PATH              Age        Attrs
    203.0.113.1/32      192.0.2.2            65536                00:14:49   [{Origin: i} {LargeCommunity: [ 65536:1:2]}]

# docker exec 153b6165385f birdcl show route all
BIRD 1.6.1 ready.
203.0.113.1/32     unreachable [ExaBGP 14:29:25 from 192.0.2.2] * (100/-) [AS65536i]
        Type: BGP unicast univ
        BGP.origin: IGP
        BGP.as_path: 65536
        BGP.next_hop: 192.0.2.2
        BGP.local_pref: 100
        BGP.large_community: (65536,1,2)
                   unreachable [GoBGP 14:29:28 from 192.0.2.3] (100/-) [AS65536i]
        Type: BGP unicast univ
        BGP.origin: IGP
        BGP.as_path: 65537 65536
        BGP.next_hop: 192.0.2.3
        BGP.local_pref: 100
        BGP.large_community: (65536,1,2)

LargeCommunity: [ 65536:1:2], BGP.large_community: (65536,1,2) - here it is!

Let's have GoBGP announce a new tagged prefix and see how ExaBGP receive it:

# docker exec ff5c323d2118 gobgp global rib add -a ipv4 203.0.113.2/32 large-community 65537:3:4
# cat exabgp/log
...
Thu, 14 Sep 2016 18:15:18 5      routes        peer 192.0.2.3 ASN 65537   << UPDATE (1) (   4)  attributes origin incomplete as-path [ 65537 ] large-community 65537:3:4

Similarly we can send a ping from one of the running containers to pmacct host to see how it handles large communities in its output:

# docker exec -it ff5c323d2118 bash
root@gobgp:/go# ping 192.0.2.5
PING 192.0.2.5 (192.0.2.5): 56 data bytes
64 bytes from 192.0.2.5: icmp_seq=0 ttl=64 time=0.185 ms
64 bytes from 192.0.2.5: icmp_seq=1 ttl=64 time=0.131 ms
64 bytes from 192.0.2.5: icmp_seq=2 ttl=64 time=0.125 ms

# cat pmacct/plugin1.out
LCOMMS,SRC_LCOMMS,SRC_IP,DST_IP,SRC_PORT,DST_PORT,PROTOCOL,PACKETS,BYTES
,65537:1:1,192.0.2.3,192.0.2.5,0,0,icmp,3,252
65537:1:1,,192.0.2.5,192.0.2.3,0,0,icmp,3,252

Since all the images EXPOSE port 179, the -p 179:179 Docker run option can be used to publish the BGP daemon outside the local host, in order to test interoperability with other software/hardware:

# docker run --net bgp-large-communities-playground --ip 192.0.2.3 -p 179:179 --hostname=gpbgp -d -v `pwd`/gobgp:/etc/gobgp:rw pierky/gobgp
# # now establish a BGP session with <your_host_ip>:179

Enjoy BGP Large Communities and have fun! ;)

Author

Pier Carlo Chiodi - https://pierky.com

Blog: https://blog.pierky.com Twitter: @pierky