>>I viewed their composite trunking feature with some uncertainty, and feel that they could have been a little more generous with their explanations, to tell you the truth.<<
Thanks for the comments. I'm not sure if the following helps, but I did find this over on their site...
>>Optical Internetworking
Avici Systems provides complementary technology designed to enhance the ODSI initiative. ODSI proposes an open signaling interface between the optical and data layers so that end-to-end dynamic provisioning and restoration can be achieved. Avici's TSR© is ideally suited to ODSI by virtue of its immense port capacity. The TSR is optimized to route traffic onto the hundreds of wavelengths that new optical equipment will provide as the network scales; enabling a smooth migration path to link rates of 40 Gbps and beyond.
The Avici TSR Composite Link feature has the ability to recognize heavy traffic demand, and dynamically add a new member(s) to the Composite Link. This result is on-the-fly creation of additional bandwidth for adapting link capacity to fluctuations in Internet traffic flows. Avici will be working with other members of the ODSI to promote protocols that enable Composite Links to summon the optical core for additional bandwidth between any two TSRs (City A to City B). A key aspect of Composite Links is the ability to add and remove links with no impact to IP routing tables. Therefore, as the composite link membership dynamically adjusts to meet network demand, the size of the IGP remains constant. There is absolutely no need to update routing tables, increasing the speed with which service providers can provision new service. ODSI coupled with MPLS traffic engineering and the Avici's TSR provides network operators the ability to offer bandwidth to the service layer in a dynamic fashion while applying resources to network hot-spots. The result is an improvement in flexibility that is significantly beyond what is currently available in today's statically provisioned networks.
Composite Links as a means for migration to OC-768
Avici Systems' Composite Links enables a smooth migration to link speeds equivalent to OC-768 by utilizing existing physical link resources at OC-12c and OC-48c speeds. The interfaces used in Composite Links can have a 4-1 speed mismatch. For example, this would allow OC-48c members to be combined with OC-12c members, so that a smooth migration path from OC-12c to higher speed trunks can be provided. Traffic is distributed over active composite link members, accommodating a 4-1 speed mismatch with weighed fair queuing at each ingress module. This is a far more intelligent load balancing scheme when compared to other methods currently in use such as Equal Cost Multi-Path (ECMP).
Composite Links Defined
A composite link is comprised of up to (16) physical links or fiber interfaces between two Avici TSRs. Upper layer protocols view these individual links as a single logical entity with an equivalent capacity of the aggregated composite members. Packet ordering is maintained at the microflow level to protect packet sequence integrity. Packet ordering is accomplished by a hash value calculated from the IP source and destination address, and used to select the Composite Link member. Each Composite Link member is a SONET interface, using Packet over SONET (POS) encapsulation. Each member is established using standard PPP protocol thus offering multi-protocol support. Although each member maintains a PPP connection, the protocol layers above; either IP or MPLS are only presented with a single, logical PPP interface, which represents the aggregate of the composite link members. When a member of a Composite Link fails, all data that was being transmitted on that link is automatically re-distributed to one of the other active Composite Link members. This re-distribution occurs in less than 45ms. <<
avici.com
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