ROUTE SERVERS (RS)
SGIX operates two Route Servers (RS) in Singapore. Once peered with the RS, there is no need to maintain multiple BGP sessions with other members in the IX. RS provide AS-path, MED, Communities and Next-hop transparency so that peering at SGIX still appear to be directly connected. As a result, members traffic are exchanged directly within SGIX switching fabric without passing through RS.
Please note the following when peering with RS
- Remove any private ASN in the prefix announcement.
- Remove any IPv4v6 default route in the prefix announcement.
- Prefixes stated in RFC 1918 are not allowed
- Disable check on first-ASN. This may be applicable to Huawei (“undo check-first-as”) and Cisco equipment (“no bgp enforce-first-as”).
- The default BGPv4v6 max-prefix threshold is set to 100 but member can request for a different value during provisioning.
- Members are advised to peer with both RS for redundancy.
- Members can choose to establish or maintain bi-lateral peering arrangement with other members.
- Members agree not to hold SGIX responsible for any impact on traffic flow due to policies request configured at RS by other members.
BGP Announcement Filtering
Besides the well-known community like NO_EXPORT and NO_ADVERTISE, members can control their prefixes announcement to other members by tagging them with SGIX BGP communities. By default, RS will advertised all prefixes to all peers.
The following table shows SGIX BGP communities in top-down evaluation order. These communities are processed by RS and not propagated to any peers.
|0:55518||Block announcement of prefixes to all ASN|
|0:ASN||Block announcement of prefixes to this ASN only|
|55518:ASN||Announce prefixes to this ASN only|
For members having 4-byte ASN, they will be mapped to private ASNs. Hence, prefixes announcement manipulation is still possible using above communities.