ROUTE SERVERS (RS)
SGIX operates two Route Servers (RS) in Singapore and filter based on AS-path and IP prefixes. BGP announcements that a route server receives from a peer are checked against the AS-SET the peer has provided and be RPKI validated.
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 IP v4v6 default route in the prefix announcement.
- Prefixes stated in RFC 1918, RFC 2544, RFC 3927, RFC 5735, RFC 5737, RFC 6598 and RFC 6980 are not allowed.
- Bogon ASNs in the AS-path 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 BGP v4v6 max-prefix threshold is set to 100 but member can request for a different value during provisioning.
Conditions
- 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 BGP standard community or large community. By default, RS will advertised all prefixes to all peers.
The following table shows BGP standard and large communities in top-down evaluation order. These communities are processed by RS and not propagated to any peers.
| Standard Community | Descriptions |
| 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 |
| Large Community | Descriptions |
| 55518:0:0 | Block announcement of prefixes to all ASN |
| 55518:0:$ASN* | Block announcement of prefixes to this ASN only |
| 55518:1:$ASN* | Announce prefixes to this ASN only |
*For members having 4-byte ASN, you have to use for the BGP Large Communities.
AS PATH Prepending
The following table contains information about how to prepend your own ASN up to three times selectively to a certain ASN peer.
| Standard Community | Descriptions |
| 65001:$ASN | Prepend once to this ASN only |
| 65002:$ASN | Prepend twice to this ASN only |
| 65003:$ASN | Prepend thrice to this ASN only |
| Large Community | Descriptions |
| 55518:101:$ASN* | Prepend once to this ASN only |
| 55518:102:$ASN* | Prepend twice to this ASN only |
| 55518:103:$ASN* | Prepend thrice to this ASN only |
*For members having 4-byte ASN, you have to use for the BGP Large Communities.
Connecting using a Routed Port
Connecting to SGIX using a routed port is the preferred design and below is the recommended port configuration (Cisco IOS). Member need to adapt this configuration to their respective platform when connecting to SGIX fabric.
GigabitEthernet X/X/X description Facing SGIX Port ip address <your_allocated_ipv4_address> ipv6 address <your_allocated_ipv6_address> no cdp enable no mop enable no ip mask-reply no ip proxy-arp no ip redirects no ip directed-broadcast no ip unreachables no keepalive no lldp transmit no lldp receive no udld enable ipv6 nd ra suppress all ipv6 nd prefix default no-advertise |
Connecting via an Intermediate Switch
The intermediate switch connecting both the customer router and SGIX MUST have a dedicated vlan with no other additional devices in that vlan. SGIX only allow two MAC addresses per port. Below is the recommended switch port configuration facing SGIX. If bpdufilter feature is not available in your platform, we recommend that member disable spanning-tree on the dedicated vlan.
vlan XXX name SGIX GigabitEthernet X/X/X description Facing SGIX Port switchport mode access switchport access vlan XXX switchport nonegotiate spanning-tree bpdufilter enable no keepalive no cdp enable no lldp receive no lldp transmit no udld enable |