What are
In an IT Company when the
As a first step, I suggest you sign up on peeringdb.com to allow your future peers to learn the basic information about your network and your NOC.
Next, prepare your
- Your ASN
- Your peer ip address
- How many and which ASNs will be behind the AS-MASTER
- Your advertised networks
- Your route-policies
- Your
ip -prefix-lists
Ask the ISP:
- His ASN
- His peer
ip address - The eventual authentication option (Es. MD5)
- Communities BGP to do traffic engineering (if requested)
An ISP can announce 3 subsets of routing tables, we can choose between:
- DFZ: >760.000 routes (aka BGP Full Route)
- PARTIAL: circa 300.000 routes + the default-route 0.0.0.0/0
- ONLY DEFAULT: 0.0.0.0/0
Little example… Customer side (Huawei BGP routers):
#Build ACLs to tag ASN into advertised networks
acl number 2010
description ASnnnn
rule 5 permit source 10.10.0.0 0.0.15.255
#
acl number 2015
description ASyyyy
rule 5 permit source 20.20.0.0 0.0.15.255
#
acl number 2020
description ASzzzz
rule 5 permit source 30.30.0.0 0.0.15.255
#
route-policy toISP permit node 10
if-match acl 2010
apply as-path [ASnnnn] additive
#
route-policy toISP permit node 15
if-match acl 2015
apply as-path [ASyyyy] additive
#
route-policy toISP permit node 20
if-match acl 2020
#nothing to apply because is the ASN-MASTER
#Build an ip-prefix to permit all Prefixes... you'll need it in the future if you need to block some networks
ip ip-prefix fromISP index 10 permit 0.0.0.0 0 less-equal 32
#Build an as-path filter to allows only locally originated routes to be advertised to that ISP neighbor
ip as-path-filter ISP permit ^$
#Finally BGP confs:
bgp [my_bgpAS]
router-id [ip-router-id]
peer [ip_isp_peer] as-number [isp_bgpAS]
peer [ip_isp_peer] connect-interface GigabitEthernet0/0/9
#
ipv4-family unicast
undo synchronization
network 10.10.0.0 255.255.240.0
network 20.20.0.0 255.255.240.0
network 30.30.0.0 255.255.240.0
peer [ip_isp_peer] enable
peer [ip_isp_peer] as-path-filter ISP export
peer [ip_isp_peer] ip-prefix fromISP import
peer [ip_isp_peer] route-policy toISP export
Have a great Internet!
.glitchlist crew
*: Italian slang