3com 3.01.01 Manuale Utente

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IPX Configuration
61
Packet length :60
Data offset: 10
Debug and trace the packets located in SYN, FIN or RST.
Operations include:
<SW8800>terminal debugging
<SW8800>debugging tcp transact
The TCP packets received or sent can be checked in real time, and the specific 
packet formats are the same as those mentioned above.
IPX Configuration
Internetwork Packet Exchange (IPX) protocol is a network layer protocol in the 
NetWare protocol suite. It is similar to IP in the TCP/IP protocol suite. IPX functions 
to address, route and forward packets.
IPX is a connectionless protocol. Though an IPX packet includes a destination IPX 
address in addition to the data, there is no guarantee of successful delivery. Packet 
acknowledgement and connection control must be provided by protocols above 
IPX. Each IPX packet is considered an independent entity that has no logical or 
sequential relationship with any other IPX packets.
IPX Address Structure
IPX and IP use different address structures. An IPX address comprises two parts: 
the network number and the node address; it is in the format of network.node.
A network number identifies the network where a site is located. It is four bytes 
long and expressed by eight hexadecimal numbers. A node address identifies a 
node on the network. Like a MAC address, it is six bytes long and written with the 
bytes being separated into three 2-byte parts by “-”. The node address cannot be 
a broadcast or multicast address. For example, in the IPX address bc.0-0cb-47, bc 
(or 000000bc) is the network number and 0-0cb-47 (0000-00cb-0047) is the node 
address. You can also write an IPX address in the form of N.H-H-H, where N is the 
network number and H-H-H is the node address.
Routing Information 
Protocol
IPX uses the Routing Information Protocol (RIP) to maintain and advertise dynamic 
routing information. With IPX enabled, the switch exchanges routing information 
with other neighbors through RIP to maintain an internetwork routing information 
database (also known as a routing table) to accommodate to the network 
changes. When the switch receives a packet, it looks up the routing table for the 
next site and if there is any, forwards the packet. The routing information can be 
configured statically or collected dynamically.
This chapter introduces RIP in IPX. For the RIP configurations on an IP network, 
refer to the routing protocol section in this manual.
Service Advertising 
Protocol
The Service Advertising Protocol (SAP) advertises the services provided by servers 
and their addresses. It is used by IPX to maintain and advertise dynamic service 
information. With SAP, a server broadcasts its services when it starts and the 
termination of the services when it goes down.
With IPX enabled, the switch creates and maintains an internetwork service 
information database (or the service information table) through SAP. It helps you 
learn what services are available on the networks and where they are provided.