ACF NCP
Encyclopedia
ACF NCP stands for Advanced Communication Function - Network Control Program. It is the program that controls network
communications in a standard SNA
.
DLSW+ is
an IP transport solution for SNA/NetBIOS between peering routers. In traditional SNA networks, ACF/VTAM
software on the host and ACF/NCP software on the FEPs together perform all routing of SNA traffic, ensuring that
the traffic flows appropriately from source to destination. Because it does not have any ACF/NCP or ACF/VTAM
functionality within it, DLSw+ routers cannot route traditional SNA traffic. Instead, DLSw+ simply encapsulates the
traffic in IP. Within the IP network the traffic is routed, but when converted back to SNA, it must continue to be
routed by ACF/NCP or ACF/VTAM.
Two issues that result from this fact have caused some IT organizations to continue to support FEPs in the data center.
First, many SNA networks implement a design in which two FEPs running ACF/NCP can act as backup for one
another. If one of the paths to one of the FEPs fails, the SNA traffic automatically can be sent through the other FEP.
Known as duplicate Token Ring interface coupler (TIC) addressing, this feature has been the centerpiece of building
high-availability SNA networks. DLSw+, although offering many high-availability features, cannot directly replace
this function. Therefore, SNA sessions can fail if one of the DLSw+ routers fails. Some IT organizations have
continued to support FEPs in the data center primarily to provide this redundancy for SNA sessions.
The second issue is host cycle conservation. As stated, ACF/VTAM and ACF/NCP work together to route SNA
traffic. If ACF/NCP is not present or is eliminated, then ACF/VTAM must take responsibility for all of the SNA
routing tasks. For organizations that do not have ample host CPU cycles idle, the increase in host processing can have
an adverse impact on application response and network performance
Steve Knockswell
CCIE 22131
Computer network
A computer network, often simply referred to as a network, is a collection of hardware components and computers interconnected by communication channels that allow sharing of resources and information....
communications in a standard SNA
Systems Network Architecture
Systems Network Architecture is IBM's proprietary networking architecture created in 1974. It is a complete protocol stack for interconnecting computers and their resources. SNA describes the protocol and is, in itself, not actually a program...
.
DLSW+ is
an IP transport solution for SNA/NetBIOS between peering routers. In traditional SNA networks, ACF/VTAM
software on the host and ACF/NCP software on the FEPs together perform all routing of SNA traffic, ensuring that
the traffic flows appropriately from source to destination. Because it does not have any ACF/NCP or ACF/VTAM
functionality within it, DLSw+ routers cannot route traditional SNA traffic. Instead, DLSw+ simply encapsulates the
traffic in IP. Within the IP network the traffic is routed, but when converted back to SNA, it must continue to be
routed by ACF/NCP or ACF/VTAM.
Two issues that result from this fact have caused some IT organizations to continue to support FEPs in the data center.
First, many SNA networks implement a design in which two FEPs running ACF/NCP can act as backup for one
another. If one of the paths to one of the FEPs fails, the SNA traffic automatically can be sent through the other FEP.
Known as duplicate Token Ring interface coupler (TIC) addressing, this feature has been the centerpiece of building
high-availability SNA networks. DLSw+, although offering many high-availability features, cannot directly replace
this function. Therefore, SNA sessions can fail if one of the DLSw+ routers fails. Some IT organizations have
continued to support FEPs in the data center primarily to provide this redundancy for SNA sessions.
The second issue is host cycle conservation. As stated, ACF/VTAM and ACF/NCP work together to route SNA
traffic. If ACF/NCP is not present or is eliminated, then ACF/VTAM must take responsibility for all of the SNA
routing tasks. For organizations that do not have ample host CPU cycles idle, the increase in host processing can have
an adverse impact on application response and network performance
Steve Knockswell
CCIE 22131