IPX(Internetwork Packet Exchange protocol)

IPX(Internetwork Packet Exchange protocol) is a specialized protocol suite, it mainly consists of Novell NetWare operating systems use. The IPX protocol cluster is the IPX layer 3 protocols.

The IPX protocol constitutes

The IPX protocol suite includes the following main agreement:

Second-ranking IPX: the third layer protocols, used for through Internet network packets for routing and forwarding, it specifies a connectionless packets, equivalent to TCP/IP protocol suite the IP protocol,

Second-ranking the SPX: order Packet switching (Sequenced Packet Exchange) agreement. Is the IPX protocol cluster layer 4 connectionless protocol, equivalent to TCP/IP protocol suite of TCP protocol,

Second-ranking NCP: NetWare Core Protocol (NetWare Protocol), provide from Core client and server connection and applications.

Second-ranking SAP: Service notifications Protocol (Service Protocol) used to repeat the IPX net notices network Service,

Second-ranking IPX RIP: Novell Routing Information Protocol (ccna Information Protocol), complete routers exchange between Routing Information and form the Routing table.

IPX address plait

The IPX network address length is 80 (bit, consists of both the first part is a 32-bit network number, the 2nd part is 48 a node number. The IPX address usually use hexadecimal number to show.

The IPX net number assigned by the website operators, can according to need to define the network number.

The IPX node number is usually network interface itself the MAC address.

The IPX protocol cannot on the ethernets encapsulation

The IPX protocol cannot on the ethernets supports the following four kinds of packaging format, also called frame format, they are:

Second-ranking Ethernet 802.3: also called primitive Ethernet, Cisco device called "novell - ether", which was NetWare version 2 to version 3.1 default frame format,

Second-ranking Ethernet 802.2, also called the SAP, is the standard of IEEE frame format, it is NetWare version 4 x to 3.12 of standard frame format,

Second-ranking Ethernet II, also called ARPA using standard Ethernet version II head format,

Second-ranking Ethernet, or SNAP by adding a SNAP in nets access protocol (SNAP) expanded the IEEE 802.2 head format.

Adopting different IPX encapsulation format between devices cannot undertake communication.

The IPX service notifications

SAP is the IPX protocol, it can serve notices notices such as the network server and to print the server and other network resources equipment address and can provide the service.

The router can monitor SAP update, establish a known services and corresponding network address the tables. The client can use on a router's SAP table get online services and address the information and direct access to relevant service.

Internet packet-switched protocol (IPX) is Novell NetWare operating system, which support in the middle of interconnected networks by packets early network protocol. The IPX is oriented to the connectionless communication data submitted to agreement - similar to TCP/IP protocol group of Internet protocol (IP) namely. Its top protocols, such as the SPX and NCP, mainly provides error recovery service.

In order to select the best path, IPX use dynamic distance vector (distance vector) Routing protocols, such as Routing Information Protocol (RIP: ccna Information Protocol) or link-state protocols (NLSP: NetWare Link State Protocol). -

The IPX Novell network address is the only to hex said. It consists of two parts: the network number and node number. The IPX net number assigned by a network administrator, long 32-bit address. Node number, usually system network interface card (NIC) medium access control (MAC) address, long 48 bits. Through the MAC address as the node number, the system can be sent through node to determine the data link using the MAC address.

Single Novell NetWare IPX router interface support four encapsulation mode:

* Novell private (Novell Proprietary) - also known as primitive 802.3 or Ethernet_802. 3, Novell Novell private companies first use of Novell is encapsulated mode.

* 802.3 - also known as Novell_802. IEEE 802.3 standard is 2,802.3 frame format.

Ethernet v * 2 - also known as Ethernet - II or ARPA, Ethernet v2 include standard Ethernet v2 agreement head, which by target address and source address fields constitute, behind is EtherType field.

* SNAP - also known as Ethernet_SNAP, SNAP in original IEEE 802.2 agreement head increased type code, and Ethernet v2 defined in the EtherType similar.

The IPX packets of data portion for 30 bytes long minimum (only head part), maximum indefinite, it mainly depends on use of low-rise MAC protocol (Ethernet or token-ring).

Agreement structure

NetWare IPX data baotou:

8 16 bit

Newer

Packet Length

Transport control Packet Type

Take a (4 bytes)

USES node (6 bytes)

USES socket (2 bytes)

Returned a (4 bytes)

Returned node (6 bytes)

Returned socket (2 bytes)

* newer -- said when 16 field all set to 1 (FFFF), do not use Checksum.

* Packet length - designated complete IPX data quote bytes long. The IPX packets size.this media, can achieve maximum transmission unit (MTU) size (not allow packet piece-wise).

* Transport control - indicating packet transmission process after router quantity. When this value is 16, assuming happen routing loops, and discarding packets.

* Packet type - specifies which upper agreement should receive this Packet information. Usually includes two values:

O 5 - said sequence packet switching (the SPX)

O 17 - said NetWare core protocol (NCP)

* USES a node, and USES, USES socket - said targets information.

* returned a node and returned, returned socket - said Source information.