An IPX address has the following structure:
Network number The network number allows to address (and communicate with) the IPX nodes which do not belong to the same network or
cabling system. The
cabling system is a network in which a
data link layer protocol can be used for communication. To allow communication between different networks, they must be connected with IPX
routers. A set of interconnected networks is called an
internetwork. Any
Novell NetWare server may serve as an IPX router. Novell also supplied stand-alone routers. Other vendors ' multiprotocol routers often support IPX routing. Using different
frame formats in one cabling system is possible, but it works similarly as if separate cabling systems were used (i.e. different network numbers must be used for different frame formats even in the same cabling system and a router must be used to allow communication between nodes using different frame formats in the same cabling system). • Logical networks are assigned a unique 32-bit address in the range 0x1 to 0xFFFFFFFE (
hexadecimal). • Hosts have a 48-bit node address, which is by default set to the 6 bytes of the network interface card
MAC address. Network addresses, which exist in addition to the node address but are not part of the MAC layer, are assigned only if an IPX router is present or by manual configuration in the network. The network address covers every network participant that can talk to another participant without the aid of an IPX router. In combination, both network and node address form an 80-bit unique identifier for each IPX node across connected logical networks. The node number itself is unique to the logical network only. • Network number 00:00:00:00 refers to the current network, and is also used during router discovery. It's also the default in case no router is present, but can be changed by manual configuration, depending on the IPX implementation. • Broadcast network number is FF:FF:FF:FF.
Node number The node number is used to address an individual computer (or more exactly, a network interface) in the network. Client stations use its network interface card
MAC address as the node number. The value FF:FF:FF:FF:FF:FF may be used as a node number in a destination address to
broadcast a packet to "all nodes in the current network".
Socket number The socket number serves to select a process or application in the destination node. The presence of a socket number in the IPX address allows the IPX to act as a
transport layer protocol, comparable with the
User Datagram Protocol (UDP) in the
Internet protocol suite.
Comparison with IP The IPX network number is conceptually identical to the network part of the
IP address (the parts with
netmask bits set to 1); the node number has the same meaning as the bits of IP address with netmask bits set to 0. The difference is that the boundary between network and node part of address in IP is variable, while in IPX it is fixed. As the node address is usually identical to the MAC address of the network adapter, the
Address Resolution Protocol is not needed in IPX. For
routing, the entries in the IPX
routing table are similar to IP routing tables; routing is done by network address, and for each network address a network:node of the next router is specified in a similar fashion an IP address/netmask is specified in IP routing tables. There are three routing protocols available for IPX networks. In early IPX networks, a version of
Routing Information Protocol (RIP) was the only available protocol to exchange routing information. Unlike RIP for
IP, it uses delay time as the main metric, retaining the hop count as a secondary metric. Since NetWare 3, the
NetWare Link Services Protocol (NLSP) based on
IS-IS is available, which is more suitable for larger networks.
Cisco routers implement an IPX version of
EIGRP protocol as well. ==Frame formats==