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Local Area Network (LAN) Emulation over InfiniBand Disclosure Number: IPCOM000019529D
Original Publication Date: 2003-Sep-18
Included in the Prior Art Database: 2003-Sep-18
Document File: 2 page(s) / 44K

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Local Area Network (LAN) Emulation over InfiniBand

  The Internet Engineering Task Force (IETF) Internet Protocol over Infiniband (IPoIB) solution stipulates a medium access control (MAC) address of 20 bytes but most implementations are written to utilize 6 bytes (48-bit ethernet addresses) only.

Suggestion for using 48-bit addresses :

Local Area Network ID (LID) + Flags + Queue Pair (QPN) = 48 bits

The suggestion is to use the Q_Key of the multicast address and not work with global IDs (GIDs) thereby confining the 'LAN' to an Infiniband (IB) subnet.

Simple solution.

Definition of Ethernet/802.x LAN over InfiniBand

1. Each IB LAN is defined as having an IB LAN ID. For the ease of implementation, the LAN ID (LID) is assigned to each IB subnet. Define it to be an 8-bit value that is assigned by the administrator.

2. Define a 48-bit MAC address that is derivable from the InfiniBand network. Step 1: The Infiniband Trade Association (IBTA) gets an organizationally unique identifier (OUI) assigned to it (in all likelihood it already has one assigned for its EUI-64 addresses).

Step 2: The local bit is always set. Step 3: The rest of the values are the 16-bit LID. Always unique in an IB subnet. Step 4: The LAN ID for the rest of the 8 bits to allow for a LAN to span multiple IB subnets since a LID can repeat in another IB subnet.

3. The address resolution is done in the standard way by the internet protocol (IP) layer. The IB-ethernet emulation driver conducts the address resolution protocol (ARP) in the standard way. The ARP packet is then reformatted with ethernet (or any 802.2 LAN) 6-byte addresses as defined in Step 2 and returned to the IP layer.

4. The transmission of the packets over IB links may require some more thought depending on the LAN being emulated.

The global route header (GRH) is always used. The next header value is set to 97 which corresponds to ETHERIP. The IB mode used is unreliable datagram (UD)...