Packet forwarding in a network

A method of routing a packet through a network, the method comprising:

• receiving the packet at a network node;
• interrogating routing information contained in a header of the packet as a compact representation of set membership to determine one or more links along which the packet is to be sent from the network node and/or to determine one or more other nodes to which the packet is to be sent from the network node;
• and
• forwarding the packet along the determined link(s) and/or to the determined other node(s);
• wherein the routing information comprises one of a plurality of candidate representations of one or more identifiers, each identifier identifying a respective network link, a respective node, or a full or partial path containing two or more network links;
• and
• wherein the routing further comprises selecting, from d look-up tables each corresponding to one of d candidate representations of the one or more identifiers, where d is an integer greater than one, a look-up table corresponding to the received representation of the one or more identifiers.

A network node for providing routing information for packets, the network node being adapted to encode the routing information from a source node to one or more destination nodes into a compact representation of set membership for inclusion into a header of a packet that is to be sent from the source node to the destination node(s), the routing information comprising representations of one or more identifiers;

• wherein the network node is adapted to encode the routing information by:
• generating d representations of at least some of the one or more identifiers, where d is an integer greater than one;
• generating d candidate compact representations of set membership from the d representations of the one or more identifiers;
• and
• selecting one of the candidate compact representation of set membership.