System information

20 IBM and Cisco LAN Switching: Interoperability and Migration Guide
For connection to a WAN, IBM 8265 supports many common
standards-based interfaces such as:
• E1,DS1 and J1
• E3 and DS3
• OC-3/STM-1 with SONET or SDH STM-1
• Inverse multiplexing of E1 or DS1 (IMA)
2.2.1.2 Interface signalling
If it is desirable to add a backbone or workgroup switch of another brand to a
network of IBM 8265 switches, customers must know which interface
signalling they need support for. All three user-to-network interface protocols
currently standardized are supported by most equipment on the market:
• UNI 3.0
• UNI 3.1
• UNI 4.0
In addition IBM 8265 supports automatic recognition and interworking (with
some limitations) between these three standards. This may have a value for
the user, but lack thereof can be worked around.
ILMI is supported on most ATM switches. In addition, IBM 8265 provides for
an access control feature that gives some protection against unauthorized
access to a port.
Public ATM networks in general do not provide switched virtual circuits, but
rather a permanent virtual path between customer equipment. When such an
interface is defined as void on the IBM 8265, multiple virtual path channels
(VPC) are supported. A VPC can operate in UNI mode, IISP mode, or PNNI
mode, or with no signalling at all. This works well for supporting all kinds of
signalling across an ATM WAN between IBM 8265 switches and user stations.
To migrate to a Cisco switch environment some network re-design may be
required, usually involving the ATM PVC being used as a high-speed
point-to-point connection between routers.
2.2.1.3 Call routing
PNNI is supported by IBM and Cisco Systems. The Catalyst and Lightstream
ATM switches support full PNNI hierarchy like IBM 8265.
2.2.1.4 Traffic management
IBM and Cisco ATM switches generally support all classes of service:
• Available bit rate (ABR)