Cabletron Systems DMS-100 manual Addressing, MAC addresses, Internet addresses

54Chapter 2: EIU messaging protocols

Upon receiving RIP update from either another EIU or IP router on the LAN, the RIP software updates internal IP routing table. According to RFC1058, RIP response messages are transmitted every 30 s to Ethernet LAN.

Addressing

Within a single SuperNode switch, multiple hosts and multiple applications within a single host may simultaneously request TCP/IP services. To provide for application address uniqueness across the network, the following TCP/IP address allocation scheme is used:

•TCP/UDP provides individual PORT numbers to distinguish between applications in the same host.

•Each host processor in the Internet SuperNode switch is assigned a unique IP address. This is a logical address, and when concatenated with TCP port number, forms a unique network end-point or “socket”.

•A unique IP address is required per hardware device.

•Within the network, each node is physically identified by its own unique physical hardware address. The logical IP address is translated to a physical hardware address prior to datagram delivery to the destination node.

•Within a SuperNode switch, each node such as DMS-core, FP, and EIU has a unique FTA, which is the physical hardware address on the SuperNode subnet. The EIU also has a media access control (MAC) address, which uniquely identifies it on the Ethernet LAN.

•IP broadcast is not supported on the SuperNode subnet since the physical layer does not support this.

MAC addresses

A unique media access control (MAC) address is assigned to each EIU through table control datafill in table LIUINV. The norm within the industry is that the MAC addresses are hard-coded in ROM. The EIU is different from industry norm in this case. There is a flexibility of assigning the MAC address to the EIU and at the same time the flexibility can result in problems if the addresses are not assigned uniquely to the EIUs.

Only 48-bit MAC addresses are supported by the SuperNode switch.

For more information on MAC addresses, refer to “Appendix I: Obtaining a MAC address”.

Internet addresses

The logical Internet address is analogous to physical or subnet addressing in which each host is assigned unique integer address called the Internet address or IP address. The Internet address integers are not assigned randomly, but are assigned to nodes in such a way that Internet routing is more efficient. Refer to

297-8991-910 Standard 03.01 August 1999