LINX maintains route servers at each of the Peering LANs allowing members to establish multilateral peering with other participants.

Connect to the Route Servers

The Route Servers use the BIRD distribution with the Ubuntu Server Linux distribution.

Technical Details are as follows:

• AS Number:8714

Server	Type	LAN	IPv4 Address	IPv6 Address
rs1.lon1	BIRD	LINX LON1	195.66.225.230	2001:7f8:4::220a:1
rs3.lon1	BIRD	LINX LON1	195.66.225.231	2001:7f8:4::220a:2
rs2.lon2	BIRD	LINX LON2	195.66.237.231	2001:7f8:4:1::220a:1
rs4.lon2	BIRD	LINX LON2	195.66.237.230	2001:7f8:4:1::220a:2
rs1.man1	BIRD	LINX Manchester	195.66.244.230	2001:7f8:4:2::220a:1
rs2.man1	BIRD	LINX Manchester	195.66.244.231	2001:7f8:4:2::220a:2
rs1.car1	BIRD	LINX Wales	195.66.228.230	2001:7f8:4:4::220a:1
rs1.sco1	BIRD	LINX Scotland	195.66.246.230	2001:7f8:4:3::220a:1
rs1.nva1	BIRD	LINX NoVA	206.55.196.230	2001:504:31::220a:1
rs2.nva1	BIRD	LINX NoVA	206.55.196.231	2001:504:31::220a:2

Policy control is done by use of BGP Standard Communities and BGP Extended Communities and BGP Large Communities. Members may tag their routes with the following to control policy via the route server.

The model is as follows:

Action	Standard Community	Extended Community	Large Community
block announcement of a route to a certain peer	0:peer-as	rt:0:peer-as	8714:0:peer-as
announcement of a route to a certain peer	8714:peer-as	rt:8714:peer-as	8714:1:peer-as
block announcement of a route to all peers	0:8714	rt:0:8714	8714:0:0
announcement of a route to all peers	8714:8714	rt:8714:8714	8714:1:8714

If none of the above communities is present then the default behaviour is to advertise the prefix to all peers.

Members can now manipulate the BGP AS_Path attribute through prepending multiple entries of an AS for prefixes they announce to the LINX Route-Servers. Members can action AS_Path prepending to deprioritize a route for an alternate path by tagging a specified community to their prefix or prefixes.

Members can either action AS-Path prepending to all members or to selective members.

The tables below show the standard, extended and large communities to perform AS-Path prepending actions.

The table below shows the communities required to be tagged to announce prefixes with AS-prepending actioned to all members peering on the route-servers.

Community type	Prepend ASN one time	Prepend ASN two times	Prepend ASN three times
Standard	8714:65501	8714:65502	8714:65503
Extended	rt:8714:65501	rt:8714:65502	rt:8714:65503
Large	8714:65501:1	8714:65502:2	8714:65503:3

The table below shows the communities required to be tagged to announced prefixes with AS-prepending actioned to selective members peering on the route-servers.

Community type	Prepend ASN one time	Prepend ASN two times	Prepend ASN three times
Standard	65501:$peer	65502:$peer	65503:$peer
Extended	rt:65501:$peer	rt:65502:$peer	rt:65503:$peer
Large	8714:65501:$peer	8714:65502:$peer	8714:65503:$peer

The maximum number of AS-Path prepends allowed is three times. If members wish to have this increased, please contact support@linx.net

LINX is validating prefixes at ingress on all route servers. The validation is based on RPKI and IRR Object presence.

For RPKI validation we build a ROA table from IRR trust anchors and for IRR Object presence we build a list of valid origin ASN and prefixes based on route objects. Refines/more specifics of valid route objects are rejected.

We are looking for a valid AS-SET in the members PeeringDB record. If no valid AS-SET is found, we use the members ASN only, unless the member has provided us other information.

The results of the validation is reflected in communities which are being added at ingress:

• 8714:65011 = Prefix is present in an AS's announced AS/AS-SET
• 8714:65021 = Prefix is not present in an AS's announced AS/AS-SET
• 8714:65010 = Prefix has valid Origin AS in AS-SET
• 8714:65020 = Prefix has no valid Origin AS in AS-SET
• 8714:65012 = Prefix is RPKI VALID
• 8714:65022 = Prefix is RPKI INVALID
• 8714:65023 = Prefix is RPKI UNKNOWN

The prefix validation will always occur, and members can check the communities being set to their prefixes, and as such see the result of the validation checks through the route server looking glass interface.

Prefixes will only be accepted on the following criteria where,

1. Prefixes tagged with communities 8714:65010 (valid Origin AS in AS-SET) & 8714:65012 (RPKI VALID) or
2. Prefixes tagged with communities 8714:65010 (valid Origin AS in AS-SET) & 8714:65011 (Prefix is present in an AS's announced AS/AS-SET) & 8714:65023 (RPKI UNKNOWN) .

All other prefixes will be filtered at egress.

Any member who prefers to receive an unfiltered set of prefixes can request to opt-out of the filtering by contact our NOC at support@linx.net.

Looking Glass for route-servers is now accessible.

Corrupt AS path & Malformed AS-Path issues

Some members who use Cisco, Brocade and Huawei devices to peer with may encounter issues in establishing peering sessions and may see notifications of invalid or corrupt AS path and Malformed AS-path in their device logs. Something similar to:

Sep 1 08:40:40.498 UTC: %BGP-5-ADJCHANGE: neighbor 195.66.225.230 Up
Sep 1 08:40:41.506 UTC: %BGP-5-ADJCHANGE: neighbor 195.66.225.230 Down BGP Notification sent
Sep 1 08:40:41.506 UTC: %BGP-3-NOTIFICATION: sent to neighbor 195.66.225.230 3/11 (invalid corrupt AS path) 11 bytes 40020802 033C3424 580097

This issue is caused where the peering device does not like to receive updates from the route-server where the first AS in the path is not the route-server AS.

To work around this please use one of the vendor specific commands in your router configuration.

Cisco/Quagga/Brocade/Arista

router bgp <ASN>
no bgp enforce-first-as

Huawei

bgp <ASN>
undo check-first-as

If members are having trouble peering with the route servers please contact support.

For more information on Route Server statistics, please look at stats.linx.net/rs.

NB: This page only lists established sessions