BGP
The Border Gateway Protocol (BGP) is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the internet. BGP is classified as a path-vector routing protocol, and it makes routing decisions based on paths, network policies, or rule sets configured by a network operator.
Configuration
Following is an example of a BGP configuration with one session.
{
"interfaces": {
"network": [
{
"interface": "eth1",
"address": "10.0.1.2/24",
"gateway": "10.0.1.1"
}
]
},
"bgp": [
{
"local-address": "10.0.1.2",
"peer-address": "10.0.1.1",
"raw-update-file": "test.bgp",
"local-as": 65001,
"peer-as": 65001,
"family": [ "ipv4-unicast", "ipv6-unicast" ]
}
]
}
{ "bgp": {} }
Attribute |
Description |
|---|---|
network-interface |
BGP local interface (source interface).
Default: first network interface from configuration
|
local-address |
BGP local IPv4/6 address (source address).
Default: network interface address
|
local-as |
BGP local AS.
Default: 65000 Range: 0 - 4294967295
|
peer-address |
Mandatory BGP peer IPv4/6 address.
|
peer-as |
BGP peer AS.
Default: local AS Range: 0 - 4294967295
|
hold-time |
BGP hold-time in seconds.
Default: 90 Range: 0 - 65535
|
id |
BGP identifier.
Default: 1.2.3.4
|
tos |
BGP IP TOS.
Default: 0 Range: 0 - 255
|
ttl |
BGP IP TTL.
Default: 255 Range: 0 - 255
|
reconnect |
Reconnect BGP session automatically.
Default: true
|
start-traffic |
Start global traffic after RAW update finished.
If enabled, the control command traffic-start is automatically
executed as soon as the BGP RAW update has finished.
Default: false
|
teardown-time |
BGP teardown time in seconds.
Default: 5 Range: 0 - 65535
|
raw-update-file |
BGP RAW update file.
|
family |
BGP families to be send in open message.
Default: ipv4/6-unicast, ipv4/6-labeled-unicast
Values:
ipv4-unicast, ipv6-unicast,
ipv4-multicast, ipv6-multicast,
ipv4-labeled-unicast, ipv6-labeled-unicast,
ipv4-vpn-unicast, ipv6-vpn-unicast,
ipv4-vpn-multicast, ipv6-vpn-multicast,
ipv4-flow, ipv6-flow, evpn
|
extended-nexthop |
BGP extended-nexthop families to be send in open message.
Default: None
Values: ipv4-unicast, ipv4-vpn-unicast
|
BGP Sessions
BGP session are opened with the capabilities for the following address families:
IPv4 unicast
IPv4 labeled unicast
IPv6 unicast
IPv6 labeled unicast
This can be changed using family configuration option.
Limitations
BGP authentication is currently not supported but already planned as an enhancement in one of the next releases.
RAW Update Files
The BNG Blaster can inject BGP messages from a pre-compiled RAW update file into the defined sessions. A RAW update file is not more than a pre-compiled binary stream of BGP messages, typically but not limited to update messages.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ +
| Marker |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Type | ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++
.
.
.
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ +
| |
+ +
| Marker |
+ +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Type | ...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-++++
Those files can be created using the included BGP RAW update generator
script bgpupdate or manually using libraries like scapy or converters
from PCAP or MRT files.
The configured raw-update-file under the BGP session is loaded
during BNG Blaster startup phase and send it as soon as the session is
established.
The bgp-raw-update command allows to send further updates during
the session lifetime.
$ sudo bngblaster-cli run.sock bgp-raw-update file update1.bgp
This allows loading a full table after the BGP session has started and manually trigger a series of changes using incremental updates files.
All BGP RAW update files are loaded once and can then be used for multiple sessions. Meaning if two or more sessions reference the same file identified by file name, this file is loaded once into memory and used by multiple sessions.
Therefore for incremental updates, it may make sense to pre-load
via bgp-raw-update-files configuration.
{
"bgp": [
{
"local-address": "10.0.1.2",
"peer-address": "10.0.1.1",
"raw-update-file": "start.bgp",
"local-as": 65001,
"peer-as": 65001
}
],
"bgp-raw-update-files": [
"update1.bgp",
"update2.bgp"
]
}
Incremental updates not listed here will be loaded dynamically as soon as referenced by the first session.
BGP RAW Update Generator
The BGP RAW update generator is a simple tool to generate BGP RAW update streams for use with the BNG Blaster.
$ bgpupdate --help
usage: bgpupdate [-h] [-a ASN] -n ADDRESS [-N N] -p PREFIX [-P N] [-m LABEL]
[-M N] [-l LOCAL_PREF] [-f FILE] [-w] [-s STREAMS]
[--stream-tx-label LABEL] [--stream-tx-inner-label LABEL]
[--stream-rx-label LABEL] [--stream-rx-label-num N]
[--stream-threads N] [--stream-pps N]
[--stream-interface IFACE] [--stream-append] [--end-of-rib]
[--append] [--pcap FILE] [--log-level {warning,info,debug}]
The BGP RAW update generator is a simple tool to generate BGP RAW update
streams for use with the BNG Blaster.
optional arguments:
-h, --help show this help message and exit
-a ASN, --asn ASN autonomous system number
-n ADDRESS, --next-hop-base ADDRESS
next-hop base address (IPv4 or IPv6)
-N N, --next-hop-num N
next-hop count
-p PREFIX, --prefix-base PREFIX
prefix base network (IPv4 or IPv6)
-P N, --prefix-num N prefix count
-m LABEL, --label-base LABEL
label base
-M N, --label-num N label count
-l LOCAL_PREF, --local-pref LOCAL_PREF
local preference
-f FILE, --file FILE output file
-w, --withdraw withdraw prefixes
-s STREAMS, --streams STREAMS
generate BNG Blaster traffic stream file
--stream-tx-label LABEL
stream TX outer label
--stream-tx-inner-label LABEL
stream TX inner label
--stream-rx-label LABEL
stream RX label
--stream-rx-label-num N
stream RX label count
--stream-threads N stream TX threads
--stream-pps N stream packets per seconds
--stream-interface IFACE
stream interface
--stream-append append to stream file if exist
--end-of-rib add end-of-rib message
--append append to file if exist
--pcap FILE write BGP updates to PCAP file
--log-level {warning,info,debug}
logging Level
The python BGP RAW update generator is a python script that uses scapy to build BGP messages. Therefore this tool can be easily modified, extend or used as a blueprint for your own tools to generate valid BGP update streams.
The following example shows how to generate a BGP update stream with IPv4 and labeled IPv6 prefixes (6PE).
100000 x IPv4 prefixes over 1000 next-hops
50000 x IPv6 prefixes over 1000 next-hops with 1000 different labels (label per next-hop)
50000 x IPv6 prefixes over 1000 next-hops with label 2
bgpupdate -f test.bgp -a 65001 -l 100 -n 10.0.0.1 -N 1000 -p 10.1.0.0/24 -P 100000
bgpupdate -f test.bgp -a 65001 -l 100 -n 10.0.0.1 -N 1000 -m 20001 -M 1000 -p fc66:1::/48 -P 50000 --append
bgpupdate -f test.bgp -a 65001 -l 100 -n 10.0.0.1 -N 1000 -m 2 -p fc66:2::/48 -P 50000 --append --end-of-rib
Per default, the file is replaced but the option –append allows it to append to an existing file. The last update to a file should include the option –end-of-rib (optional).
The option –streams <file> (-s) automatically generates corresponding traffic streams for all prefixes. Per default, this file is replaced but the option –stream-append allows appending to an existing file.
bgpupdate -f test.bgp -a 65001 -l 100 -n 10.0.0.1 -N 1000 -p 10.1.0.0/24 -P 100000 -s streams.json
bgpupdate -f test.bgp -a 65001 -l 100 -n 10.0.0.1 -N 1000 -m 20001 -M 1000 -p fc66:1::/48 -P 50000 --append -s streams.json --stream-append
bgpupdate -f test.bgp -a 65001 -l 100 -n 10.0.0.1 -N 1000 -m 2 -p fc66:2::/48 -P 50000 --append --end-of-rib -s streams.json --stream-append
There are several options supported to further define the traffic streams like PPS and expected RX labels.
BGP Convergence Testing
The following project demonstrates how to measure the convergence between the BGP Control-Plane (CP) and the Data-Plane (DP) using the BNG Blaster. By utilizing BNG Blaster, we can analyze and monitor the time it takes for routing changes to propagate from the control-plane, where BGP updates occur, to the data-plane, where actual data packet forwarding happens.