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

Chapter 4. Connectivity 117

Advantages

The advantages of implementing an OSA-Express port in QDIO mode over non-QDI O (for

example, LCS) are:

򐂰 IP-Assist to handle MAC addressing, ARP processing, some filtering

򐂰 Dynamically maintains the OSA Address Table in a shared environment

򐂰 Supports high-speed LPAR-to-LPAR communication

򐂰 Direct Memory Access (DMA) protocol reduces IO interrupts

򐂰 Supports outbound priority queuing

򐂰 Network definitions built dynamically

򐂰 Only QDIO is capable of delivering high-bandwidth and high-speed networking

򐂰 Supports VLAN IDs to isolate services without creating independent TCP/IP stacks

Considerations

When planning connectivity for a LAN environment, there may not be a requirement to isolate

data traffic or services for certain servers or clients as we have shown in this scenario.

Hence, VLAN IDs can be omitted.

If there is a requirement for VLANs, however, we recommend adding the VLAN IDs to your IP

addressing scheme to aid in the mapping of IP addresses to VLANs based on data traffic

patterns or access to resources.

Also, to simplify administration and management of VLANs consider using Generic Attribute

VLAN Registration Protocol wherever possible. For details, refer to “VLAN support of Generic

Attribute Registration Protocol - GVRP” on page 109.

4.3.2 HiperSockets connectivity

HiperSockets provides very fast TCP/IP communications between different Logical Partitions

(LPARs) through the system memory of the System z9 or zSeries server. The LPARs that are

so connected form an

internal LAN, passing data between the LPARs at memory speeds,

and thereby totally eliminating the I/O subsystem overhead and external network delays.

To create this scenario, we define the HiperSockets, which is represented by the IQD CHPID

and its associated devices. All LPARs that are configured to use the shared IQD CHPID have

internal connectivity and therefore have the capability to communicate using HiperSockets.

In our test environment we will use two IQD CHPIDs, F4 and F5. Each one of them will create

a separate logical LAN with its own subnetwork. Figure 4-9 on page 118 depicts these

interfaces to our test scenario.

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

Figure 4-9 HiperSockets implementation scenario

Dependencies

The dependencies are:

򐂰 The HiperSockets must be defined as CHPID type IQD to the server using HCD or IOCP.

This CHPID must be defined as shared to all LPARs that will be part of the HiperSockets

internal LAN (see Example 4-1 on page 122).

򐂰 When explicitly defined, a correspondent TRLE must be created in VTAM using a port

name IUTIQDxx, where xx is the CHPID number.

򐂰 When more than one IQD CHPID is configured to a specific LPAR, VTAM start option

IQDCHPID must be used to specify which specific IQD CHPID this LPAR should use.

Advantages

HiperSockets can be used to communicate among consolidated servers within a single

System z9 or zSeries server. All the hardware boxes running these separate servers can be

OSA IP addresses

2080: 10.10.2.232

20A0: 10.10.3.233

20C0: 10.10.2.234

20E0: 10.10.3.235

HiperSockets IP addresses

CHPID F4: 10.10.4.234

CHPID F5: 10.10.4.235

CHPID F6: 10.10.5.236

z/OS LPAR: A23

Static VIPA: 10.10.1.230

OSA IP addresses

2080: 10.10.2.242

20A0: 10.10.3.243

20C0: 10.10.2.244

20E0: 10.10.3.245

HiperSockets IP addresses

CHPID F4: 10.10.4.244

CHPID F5: 10.10.4.245

CHPID F6: 10.10.5.246

z/OS LPAR: A24

Static VIPA: 10.10.1.241

OSA IP addresses

2080: 10.10.2.222

20A0: 10.10.3.223

20C0: 10.10.2.224

20E0: 10.10.3.225

HiperSockets IP addresses

CHPID F4: 10.10.4.224

CHPID F5: 10.10.4.225

CHPID F6: 10.10.5.226

z/OS LPAR: A22

Static VIPA: 10.10.1.221

CHPID: F4

Devices: E800-E81F

CHPID: F5

Devices: E900-E91F

CHPID: F6

Devices: EA00-EA1F

IP Network

OSA-Express 1000BASE-T

HiperSockets

System z9

CHPID 04

20C0-20CF

CHPID 05

20E0-20EF

CHPID 02

2080-208F

CHPID 03

20A0-20AF

Cisco

6509

Cisco

6509

Note: In both cases, the TRLE is dynamically built by VTAM. The IQDCHPID VTAM

start option controls the VTAM selection of which IQD CHPID (and related devices) to

include in the HiperSockets MPC group (IUTIQDIO) when it is dynamically built for

DYNAMICXCF connectivity.

For additional details regarding how to configure a user-defined HiperSockets device or

interface, refer to z/OS V1R7.0 Communications Server: IP Configuration Reference,

SC31-8776.