By David Le Goff – 6WIND Product Marketing Manager
IP Forwarding Characteristics
Wikipedia defines IP Forwarding as follows: “IP forwarding is a process used to determine over which path a packet can be sent. The process uses routing information to make decisions and is designed to send a packet over multiple networks”. While this definition might give the impression that forwarding packets is a straightforward task, achieving high performance on processor-based platform presents significant challenges because of the number of routing tables that must be handled.
The 6WINDGate packet processing software provides a full solution for IP Forwarding, with the capacity to handle thousands of routing table instances through its Virtual Routing and Forwarding (VRF) function.
Implemented in the 6WINDGate fast path, the IP Forwarding module provides the following features:
- Fast path-based IPv4 input, output and forwarding functions
- Virtual Routing and Forwarding (up to 2048 VRs)
- ECMP including preferred interfaces
- Jumbo frames up to 9K
- Packet rescheduling for logical interfaces
- 4in4 tunneling
Static Routing benefits
The 6WINDGate IP Forwarding function achieves wire-speed performance on static routing while providing a generic, hardware-independent packet buffer API for applications. The IP Forwarding function is implemented using a lockless M-trie algorithm for Layer 3 route lookup and its performance scales linearly with the number of cores configured to run the fast path.
While the majority of packets are processed in the fast path, the IP forwarding function handles some exceptions in the networking kernel, for example:
- wrong packets (ethertype, checksum)
- IP options
- TTL = 0
- broadcast/multicast frames
- reserved IP destination addresses
- unknown ARP entries
- unknown route entries
- route entry through a Slow Path interface (PCI, WiFi, etc)
Thanks to protocol optimizations as well as the fast path architecture, 6WINDGate processes up to 160 Mpps on a dual-socket Intel Sandy Bridge platform, enabling OEMs to implement high-end networking equipment on a unified platform architecture while achieving high static routing performance.