Communications Server for z/OS V1R7 TCP/IP Implementation, Volume 1: Base Functions, Connectivity, and Routing

Chapter 4. Connectivity 109

򐂰 Staff in different physical locations retain common access to resources.

The server is used by staff in both buildings. By defining these workstations to the same

VLAN, no additional configuration or equipment is required for either location to access

the server, while at the same time ensuring that other staff do not obtain access.

򐂰 Consolidation of resource access.

The external network has to be accessed by different staff in both buildings. Extending

VLAN 102 across to the router port in Switch 1 (and configuring the router correctly) saves

having to provide an additional link to the external network or the router from the other

building.

VLAN support of Generic Attribute Registration Protocol - GVRP

GVRP is defined in the IEEE 802.1P standard for the control of IEEE 802.1Q VLANs. It can

be used to help simplify networking administration and management of VLANs. With GVRP

support, an OSA-Express2 port can register or de-register its VLAN IDs with a GVRP-capable

switch and dynamically update its table as the VLANs change. Support of GVRP is exclusive

to System z9 and is applicable to all of the OSA-Express2 features when in QDIO mode. It is

supported by z/OS Communication Server 1.7 with PTF UQ06129 applied. Defining

DYNVLANREG in the LINK statement of the OSA-Express2 port will enable GVRP.

OSA-Express router support

OSA-Express also provides primary (PRIRouter) and secondary (SECRouter) router support.

This function allows a single TCP/IP stack, on a per-protocol (IPv4 and IPv6) basis, to register

and act as a router stack base on a given OSA-Express port. Secondary routers can also be

configured to provide for conditions in which the primary router becomes unavailable and the

secondary router takes over for the primary router

VLAN and primary/secondary router support

The OSA-Express primary router support takes into consideration and interacts with the

VLAN ID support (VLAN ID registration and tagging). OSA-Express supports a primary and

secondary router on a per-VLAN basis (per registered VLAN ID). Therefore, if TCP/IP is

configured with a specific VLAN ID and also configured as a primary or secondary router, that

stack serves as a router for just that specific VLAN. This allows each OSA-Express (CHPID)

to have a primary router per VLAN. Configuring multiple primary routers (one per VLAN) has

many advantages and preserves traffic isolation for each VLAN.

For more information regarding OSA-Express features and capabilities, refer to OSA-Express

Implementation Guide, SG24-5948.

4.2.2 HiperSockets (MPCIPA)

HiperSockets, also known as internal Queued Direct I/O (iQDIO), is a hardware feature that

provides high-speed communicating LPAR-to-LPAR within the same sever (via memory). It

also provides secure data flows between LPARs and high availability, providing there is no

network attachment dependency or exposure to adapter failures.

The HiperSockets device is represented by the IQD CHPID and its associated subchannel

devices. All LPARs that are configured in HCD to use the same IQD CHPID have internal

connectivity and therefore have the capability to communicate using HiperSockets.