IBM Understanding HiperSockets: CHPID, Number of Sockets, and LPAR Connectivity

HiperSockets

HiperSockets, a function unique to the zSeries, provides a “TCP/IP network in the server” that allows high-speed any-to-any connectivity among virtual servers (TCP/IP images) and LPARs within a zSeries system without any physical cabling. HiperSockets decreases network latency and increases bandwidth between combinations of Linux, z/OS and z/VM virtual servers. These OS images can be

first level (directly under an LPAR), or second level images (virtual servers under z/VM).

With new support for up to 16 HiperSockets the z990 pro- vides four times more HiperSockets, and up to 4,096 TCP/ IP images (stack) connections, which is also four times more capacity than the z900. The increased HiperSockets capacity and expanded connectivity provides additional

flexibility in designing the networking to accommodate con- solidated and multiple partitioned systems. HiperSockets can be divided among Logical Channel SubSystems for separation between various LPARs, while at the same time a single LPAR could have access to all 16 HiperSockets if the HiperSockets all are assigned to the same LCSS.

A HiperSockets channel also supports spanned chan- nels in order to communicate between LPARs connected to different LCSSs. HiperSockets (IQD CHPID type) can be confi gured to Channel SubSystems and transparently shared by any or all confi gured LPARs without regard to the LCSS to which the LPAR is confi gured. This means one HiperSockets could be common to all 30 z990 LPARs. This support is exclusive to z990. Different HiperSockets can be used for security (separation of traffi c, no external wire-tap- ping, monitoring) and performance and management rea- sons (separate sysplex traffi c, Linux or non-sysplex LPAR traffi c).

z/VM				z/OS	Linux		z/VM	Linux			Linux
				LPAR	LPAR		LPAR	LPAR			LPAR
LPAR 1
				14		15	17	18			30
			LCSS0					LCSS1
	MIF-1 MIF-2			MIF-F			MIF-1 MIF-2 MIF-3			MIF-F
CHPID CHPID CHPID CHPID				CHPID		CHPID	CHPID CHPID		CHPID CHPID CHPID
00	01	02	03		FF		00	01	05	22	FF
			Share			04			Share
PCHID PCHID PCHID				PCHID		SPAN	PCHID PCHID			PCHID PCHID
010B	010C	010D		020A			0245	0246		0248	0249

HiperSockets CHPID 03 HiperSockets CHPID 05

HiperSockets CHPID 04

HiperSockets does not use an external network, therefore, it can free up system and network resources, reducing attachment cost while improving availability and perfor- mance. HiperSockets can have signifi cant value in server consolidation, for example, by connecting multiple Linux virtual servers under z/VM to z/OS LPARs within the same z990. Furthermore, HiperSockets can be utilized by TCP/IP in place of XCF for sysplex connectivity between images which exist in the same server. Thus z/OS TCP/IP uses HiperSockets for connectivity between sysplex images in the same server and uses XCF for connectivity between images in different servers. Management and administration cost reductions over existing confi gurations are possible.

HiperSockets acts like any other TCP/IP network interface, so TCP/IP features like IP Security (IPSec) in Virtual Private Networks (VPN) and Secure Sockets Layer (SSL) can be used to provide heightened security for fl ows within the same CHPID. HiperSockets supports multiple frame sizes, which is confi gured on a per HiperSockets CHPID basis.

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