Link Aggregation

Link aggregation allows for the bundling of two or more links into one virtual channel towards the shared fabric, negating the need for additional routers. Link aggregation is also known as EtherChannel, Port Channel, Port aggregation or trunking, depending on the vendor involved. The IEEE 802.3ad or LACP specifications is applicable.

Pricing and Availability

AMS-IX currently offers link aggregation on Gigabit Ethernet links and larger. Link aggregation is not available on Ethernet and Fast Ethernet links. The port prices for aggregated links are identical to the normal port prices.

Due to technical limitations of the switches used by AMS-IX it may be necessary to relocate your existing port. If this turns out to be the case, AMS-IX will inform you and advise you of any additional steps necessary for this process.

AMS-IX can deliver aggregated links at all co-locations.

Although a strict reading of the spec forbids it, we can offer aggregated links over different media types of the same speed. Aggregating links acquired from different partners or resellers, however, is not supported.

Load-Balancing Algorithm for the BigIron RX and NetIron MLX platforms

The load-balancing algorithms used in our NetIron MLX switches uses a modulo operation, leading to the best distribution over links with the entropy available in source and destination IPv4 or IPv6 address, TCP or UDP source and destination port number, as applicable.

LACP & AMS-IX Topology

LACP is supported at AMS-IX for all connection types. When used with 10Gbit/s and 100Gbit/s links (where available) use of LACP does introduce an inconvenient side effect. After a topology failover ports with LACP enabled will stay in blocking mode until the first LACP frame is received. Because this may take several tens of second (depending on vendor implementation) this can cause BGP sessions to flap.

When enabling LACP we advise to configure the LACP timeout to short, to limit the maximum failover time to 3 seconds.

Configuration Hints

We have collected information about link aggregation for several router platforms in our config-guide.