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Megaport Documentation
IX Requirements
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IX Requirements

Before configuring your IX connection, ensure that you meet these requirements:

  • Permitted traffic types – All frames forwarded to the Internet Exchange must be Ethernet II (DIX), using ARP (0x0806), IPv4 (0x0800), or IPv6 (0x86DD) Ethertypes.

  • First ASN – In a standard BGP configuration the first ASN in the path will match the peer ASN. In multi-lateral peering, the first ASN is the downstream peer that provides the routes. This reduces AS path lengths for correct routing decisions. To permit multi-lateral peering, configure your devices so they do not enforce the first AS requirement. For example, on a Cisco router the command is no bgp enforce-first-as.

Recommendation

To avoid any unneeded layer 2 frames towards the IX, a VLAN tagged MegaIX service is recommended.

Note

To prevent members from sending all the internet routes to Megaport, we limit the number of prefixes (MaxPFX) that Megaport can receive. The default limit is 1000 IPv4 routes and 100 IPv6 routes. Exceeding this value results in ending the session, however you can contact Megaport support if you require a reset.

Illegal traffic types

The following frames are not permitted on the Internet Exchange:

  • Multiple MAC addresses – MegaIX operates on the principle of one router per port, meaning that frames must have the same source MAC address behind each port in each VLAN. Some members connect through intermediate switches or use a Layer 2/Layer 3 hybrid device. If these devices are not configured properly they can cause forwarding loops, STP instabilities, and unwanted traffic on the Exchange.

  • Multicast and broadcast (with the exception of ARP and IPv6 neighbor discovery) – Only exchange unicast routes over your BGP sessions in the Peering LANs. Multicast traffic is not permitted on (unicast) Peering LANs.

  • Frames from Proxy ARP – Peering VLAN traffic is exchanged based on BGP routes, so it is unnecessary to answer ARP queries for any IP addresses other than those configured on your MegaIX interface. Some vendors enable Proxy ARP by default, which can lead to unwanted traffic on your network. If you have Proxy ARP enabled at MegaIX, it is likely to be enabled at other peering points, which allows parties on both sides to use you as a transit.

  • LLC/SNAP (Subnetwork Access Protocol) frames – LLC/SNAP encapsulation (802.2) is not permitted because the IX infrastructure is based on the Ethernet II standard.

  • STP (Spanning Tree) – Devices connected to the MegaIX port are not permitted to be visible as Layer 2 bridges, and should not use STP or any other proprietary L2-specific protocol.

  • Vendor discovery protocols (CDP, EDP, FDP, MNDP) – Some vendors (e.g. Cisco and Extreme Networks) run discovery protocols by default. Running discovery protocols should be avoided as it can cause unwanted broadcast or multicast traffic.

  • Internal routing protocols (OSPF, EIGRP, IGRP, and ISIS) – BGP is the only routing protocol permitted on the Peering VLANs. Interior routing protocols only cause unnecessary multicast and broadcast traffic.

  • Cisco Layer 2 keepalives – By default, Cisco routers and switches periodically test their Ethernet links by sending out loopback frames (Ethertype 0x9000) addressed to themselves. In a switched environment, this tests the functionality of the switch and keeps the router’s MAC address in the switch’s address table. In the MegaIX environment, this is not useful because MAC timeouts are longer than the typical BGP or ARP timeouts.

  • Non-unicast IPv6 (IPv6 ND-RA) – IPv6 hosts on the MegaIX are not autoconfigured, and can cause IPv6 router advertisements to generate unnecessary traffic.

  • Non-unicast IPv4 (IGMP, DHCP, TFTP) – Do not configure multicast on the MegaIX interface. The Peering LAN is for unicast IP traffic only. The only permitted non-unicast traffic is an ARP query.

  • Trunking protocols – On Cisco Layer 2 devices such as the 2900 and 3500 series, disable VTP (VLAN Trunking Protocol), DTP (Dynamic Trunking Protocol), LLDP, and UDLD.

  • Non-IP protocols – Some vendors enable protocols other than IP by default. For example, in some versions of IOS Cisco enables MOP (Maintenance Operation Protocol). Non-IP traffic is not appropriate for the MegaIX environment.

Important

Megaport imposes a set of restrictions to ensure smooth operation of the MegaIX. Megaport reserves the right to temporarily disable offending services in order to maintain the health and stability of the MegaIX.

Exceptions

Link-local protocols ARP and IPv6 ND (Neighbor Discovery) are exceptions, and are permitted.

Additional considerations

There are some considerations when thinking about configuring an IX peering arrangement:

  • MegaIX route servers do not recognize the BGP community attribute no-export. This community attribute is passed transparently to the other peers connected to the route server.

  • Multiple Exit Discriminator (MED) values are considered in the route selection rules only when the advertising ASN is the same for candidate routes. MED values are not modified by the route servers. Values advertised to the route servers are passed unaltered to other peers.

  • All routes on the IX are given equal local preference by the route servers. The route servers do not compare the BGP router ID for best route selection, instead preferring the oldest route when all other attributes are equal.

  • Do not configure “network 194.146.118.0/24” or any of the other peering LANs in your router’s BGP configuration.

IX pricing estimates

Remote (non same metro) IX pricing is the same as VXC. An IX in the same metro as a Port is no charge, an IX in a different metro to a Port is charged at VXC rates. In the Megaport Portal, you can test different IX configurations without any obligation, to obtain a price estimate.
For more information, see VXC Pricing and Contract Terms.

Helpful references