Verilink 9000 Series (34-00271) Product Manual - Manual (Page 24)

2 C HAPTER 1: G ENERAL
With integrated SNMP in-band management, enterprise managers can now manage
TXPORT MultiPro platforms and their integral CSU/DSUs as a single unit. With
only one LAN segment in the network, all TXPORT MultiPro platforms can be
managed by SNMP. With the self-learning functionality, the MultiPro platforms
learn their frame relay environment and eliminate the need for remote, trained
personnel. By downloading all configuration parameters from the central site, no
interaction is required at remote sites to establish connectivity. WANs can be
constructed using frame relay, X.25, ISDN, or leased-line services. TXPORT
MultiPro plaforms support the listed transmission media and allow any port to be
configured for any of these technologies through simple software configuration.
Network managers can now fine tune the enterprise network for the lowest cost
and highest performance. Complete protocol spoofing and local acknowledgment
eliminates any unnecessary WAN traffic.
TXPORT MultiPro platforms provide up to a 4-to-1 data compression ratio for
both legacy and LAN protocols. This advantage enables faster file transfers and
allows purchasing a lower cost CIR (committed information rate) which reduces
monthly telecommunications costs.
Principles and
Concepts TXPORT MultiPro platforms operate based on a set of principles and concepts.
These concepts are critical in understanding how the platforms work and in
performing any troubleshooting.
Message
Delivery
System
TXPORT MultiPro platforms are message-delivery platforms. They deliver one
message at a time for any individual station. Subsequent messages are not accepted
from or for delivery to a station until the previous message is delivered. Although
the platforms have many switch-like features, they still accumulate data as
messages and then deliver them.
Endpoint-to-
Endpoint
Connectivity and
Station Level
Routing
All stations, hosts, and MultiPro Plaform units are assigned a name. All logical
connections are established based on these names. This means that any device can
connect to any other device. Under normal operation, a terminal connects to a host,
however, since each terminal has a unique name, it can also become a destination.
Each device establishes its own logical connection to an endpoint. This allows the
platform to perform station-level routing. In essence, each terminal on a port can
have a connection to a different host.
The way in which MultiPro platforms refer to these names is somewhat unique.
For each name assigned to a device, the MultiPro plaform calculates a 16-bit
cyclic redundancy checksum (CRC) the same as it would for one message of
Bisync data. This CRC then becomes the marker for that device. This way the unit
only needs to pass 16 bits of data to another task or unit when referring to a
destination.
Data Integrity The MultiPro Plaform operates under the assumption that it loses no data. Once
data is acknowledged by the MultiPro Plaform, it is delivered. The MultiPro
Plaform uses higher-layer-error and data-loss checking to ensure that no message
is lost.