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

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

4.1 What we mean by connectivity

Connectivity is the pipeline through which data is exchanged between clients and servers via

physical and logical communication interfaces and the network. The IBM System z9 and

zSeries servers provide a wide range of interface options for connecting your z/OS system to

an IP network or to another IP host. Some interfaces offer point-to-point or point-to-multipoint

connectivity, while others support Local Area Network (LAN) connectivity. Figure 4-1 depicts

the physical interfaces (and device types) provided by System z9 and zSeries servers. The

physical network interface is enabled through z/OS Communications Server (TCP/IP)

definitions.

Figure 4-1 System z9 and zSeries - Physical interfaces

Connectivity within the System z9 or zSeries servers is provided by internal or logical

interfaces such as SAMEHOST or HiperSockets.

4.1.1 Basic concepts

Network connectivity is handled by the physical and logical interfaces to enable transport of

IP datagrams. Using the OSI model as an example, it is Layer 1 (physical layer) and Layer 2

(Data link control Layer). The z/OS Communications Server has implemented several types

of interfaces to connect to different networking environments. These environments vary from

point-to-point connections, like MPCPTP, CTC, and CLAW to LAN connections such as LCS

and MPCIPA (as shown in Figure 4-1). The supported interfaces are as follows:

ATM Enables TCP/IP to send data to an asynchronous transfer mode

(ATM) network using an OSA-Express ATM adapter over an ATM

virtual circuit.

CDLC ESCON® attachments can be used to provide native IP transport,

using the channel data link control (CDLC), between the 3746 IP and

host systems running the z/OS Communications Server. The host

CTC (FICON

or ESCON)

System

p/pSeries

or OEM

Servers

HYPERchannel

CLAW

MPCPTP

MPCPTP (XCF)

CF

Sysplex

Environment

CDLC (NCP)

3745/3746

System z9/zSeries

Servers

Tok e n R i ng

Ethernet

LCS/MPCIPA

(GbE)

LCS/MPCIPA (FENET)

(1000BASE-T)

MPCIPA

(10 GbE LR)

ATM

Network

ATM (Native)

ATM (LANE)

LCS/MPCIPA