gtpc1m1y | Transmission Control Protocol/Internet Protocol |
The three types of local IP addresses are:
A maximum of 250 IP addresses can be defined for all OSA-Express connections in the TPF system. This includes real OSA IP addresses and VIPAs. You can define as many as 16 local CDLC IP addresses for each TPF host. A TPF IP address is associated with either 374x IP routers or with an OSA-Express card; therefore, a socket which is bound to a specific local IP address uses either 374x connections or OSA-Express connections, but not both.
CDLC local IP addresses are associated with 374x IP routers.
Enter the ZTTCP DEFINE command to define the IP addresses of the TPF host. You must do this before you define the IP routers to the TPF system.
If your network configuration changes and you need to delete a local IP address on your TPF host, enter the ZTTCP DELETE command. See TPF Operations for more information about the ZTTCP DELETE command.
To delete the local IP address, no IP router can be associated with this local IP address. If there are IP routers associated with this local IP address, you must first change or delete the IP router definitions before you delete the local IP address.
The default local IP address cannot be deleted if one or more local IP address is defined. If more than one local IP address (including CDLC, real OSA, and VIPA) is defined and you want to delete the IP address that is currently the default, do the following:
When a TPF host connects to more than one physically separate IP network, the TPF host has more than one local IP address defined. You can define a CDLC local IP address to be restricted to prevent remote clients in one IP network from accessing TPF applications that reside in a different IP network.
For example, assume a TPF host is connected to a private intranet and to the Internet. The TPF system uses IP address 1.1.1.1 to connect to the intranet and IP address 2.2.2.2 to connect to the Internet. IP address 1.1.1.1, port 5001, represents a server application in your TPF system that can be accessed only by clients in the intranet. To prevent clients in the Internet from accessing this application, define IP address 1.1.1.1 as restricted in your TPF system. For example, if an IP packet is received by the TPF system with a destination in the packet of IP address 1.1.1.1 and the packet is not received by an IP router connected to IP address 1.1.1.1, the TPF system will then reject the IP packet.
To define an IP address as restricted, specify RESTRICT=YES on the ZTTCP DEFINE command. You can change an IP address to be restricted by specifying RESTRICT=YES on the ZTTCP CHANGE command.
See TPF Operations for more information about the ZTTCP commands.
Real OSA IP addresses are associated with OSA-Express connections.
You must define one unique real OSA IP address of the TPF system for each OSA-Express connection and this IP address must be in the subnet of the Ethernet connected to the OSA-Express card. For example, if the Ethernet is network 9.117.249.x (with a subnet mask of 255.255.255.0), the real OSA IP address of the TPF host could be 9.117.249.31 but could not be 9.117.222.31. The real OSA IP address of the TPF host is defined to the TPF system by entering the ZOSAE command with the DEFINE or MODIFY parameter specified.
Real OSA IP addresses are tied to a fixed connection and cannot be moved. TPF applications can bind to a local IP address that is either a real OSA IP address or a VIPA. A real OSA IP address for an OSA-Express connection or a VIPA can also be defined as the default local IP address of the TPF system. If sockets are bound to a real OSA IP address and the OSA-Express connection fails, the sockets will fail. Therefore, it is recommended that you use VIPAs in your production system.
You can delete the real OSA IP address of the TPF host and all of the VIPAs associated with the connection by entering the ZOSAE command with the DELETE parameter specified. When the ZOSAE command is entered, the OSA-Express connection must be inactive, and must not have a backup defined. If the real OSA IP address or any VIPA associated with the OSA-Express connection is defined as the default IP address, and there are other local IP addresses (CDLC or OSA) defined, you cannot delete it. See TPF Operations for more information about the ZOSAE command.
In addition to CDLC and real OSA IP addresses, VIPAs can be associated with the TPF system across an OSA-Express connection. VIPAs are not fixed and can be moved from one OSA-Express connection to another or from one physical processor to another in the same loosely coupled complex.
If an OSA-Express card fails, or the switch or router connected to the card fails, any TPF VIPAs assigned to that card automatically swing to the alternate OSA-Express connection on the same processor if one is defined and is active. This enables sockets to remain active and eliminates single points of failure in network-attached hardware. The VIPAs cannot reside in the same subnet as the real IP address of the OSA-Express connection or the real IP address of the alternate OSA-Express connection if one is defined.
A static VIPA always resides on one specific TPF processor in the loosely coupled complex. A static VIPA can swing from one OSA-Express connection to another, but always on the same processor. Use static VIPAs to access processor unique TPF applications.
A movable VIPA can be defined on more than one processor in a loosely coupled complex, but is active on only one TPF processor at a time. You must define the VIPA as movable to all the processors that may potentially use it. Use movable VIPAs to access processor shared applications and to load balance TCP/IP traffic in the complex.
If you move a VIPA from one processor to another, all existing sockets using that VIPA will fail; when the remote clients reconnect to that VIPA, new sockets will be established on the new processor where that VIPA is now active. By moving a VIPA, you move all traffic for the remote users connected to that VIPA from one processor to another. A VIPA can be moved in the following ways:
To define a VIPA to an OSA-Express connection, enter the ZOSAE command with the ADD parameter specified and then specify the type of VIPA you want by doing the following:
When you define a VIPA, it is defined to a pair of OSA-Express connections (primary and alternate, if the alternate is defined), but it is only active on one OSA-Express connection at a time.
VIPAs can be defined to an active OSA-Express connection and the VIPAs can be used immediately.
To display a VIPA, do one of the following:
See TPF Operations for more information about the ZVIPA command.
To delete a VIPA definition on a processor, enter the ZOSAE command with the REMOVE parameter specified. Once you do this, that VIPA is disassociated from its OSA-Express connection and is deleted from the processor on which the message was issued. Enter the ZOSAE command with the REMOVE parameter specified only when the OSA-Express connection associated with the VIPA and its backup OSA-Express connection are not active.
You cannot delete a VIPA when it is defined as the default local IP address.
See TPF Operations for more information about the ZOSAE and ZVIPA commands.