Travel Report: Linley Carrier Ethernet Seminar Recap
Recently, I spoke at the Linley Group’s Carrier Ethernet Design Seminar, discussing the migration to packet-based fabrics in the context of supporting legacy time domain multiplexed (TDM) traffic in mixed service system architectures.
In all, the show provided an interesting look into the migration of carrier networks and the role Ethernet fabrics will play in this evolution. The presentation was timely because acquisitions have shaken up the market for cell-based backplane fabrics, leaving companies in the ecosystem wondering what the long-term health of cell-based fabrics might be.
During my presentation, I pointed out that silicon solutions for TDM are too expensive at 40G and above. Additionally, with Ethernet at 40G and moving toward 100G, a number of vendors are adopting it because of its cost advantage. I also laid out a three-phase evolution that we’re seeing in the market; from completely TDM based networks, to hybrid TDM/packet networks and finally to completely packet-based networks.
Phase one is the expensive, legacy architecture with TDM-only fabric necessitating the SARing of all packet traffic. Phase two adds a second packet fabric for native IP traffic, but also adds system cost. In phase three, we move to an Ethernet backplane that features advanced congestion management providing bounded latency for efficient TDM transport.
This low cost Carrier Ethernet-based solution is only possible with the proper features built into the Ethernet fabric. By providing TDM traffic with separate memory partitions and watermarks, it can be effectively isolated from packet traffic. In addition, advanced egress schedulers using minimum bandwidth guarantees can provide bounded latency, which is required for the proper reassembly of TDM flows.
Packet-based traffic will inevitably dominate the carrier networks. My presentation outlined one way in which cost effective Ethernet backplane fabrics can evolve to meet the needs of these networks while also providing transport for legacy TDM traffic, but we would be interested to hear your thoughts on how this evolution will take place.
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