Технические ссылки для Cisco Cisco IOS Software Release 12.2(27)SBC
Cisco SSG-to-ISG DSL Broadband Migration Guide
ISG Overview
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Cisco SSG-to-ISG DSL Broadband Migration Guide
Figure 1
Cisco SSG Architecture
The ISG software provides a structured framework in which access edge devices can deliver flexible and
scalable services to subscribers.
scalable services to subscribers.
shows the architecture that represents the new model for
offering subscriber services from access edge devices. For the ISG, a service is a collection of features
that are applicable to a subscriber session. The service is not necessarily associated with a destination
zone or a particular uplink interface.
that are applicable to a subscriber session. The service is not necessarily associated with a destination
zone or a particular uplink interface.
Figure 2
Cisco ISG Architecture
The traffic classification component of the ISG model is a set of criteria by which a traffic stream can
be refined. A traffic class is specified by means of an access control list (ACL), and would be defined
for, as an example, all User Datagram Protocol (UDP) packets or all packets destined to a particular
subnetwork.
be refined. A traffic class is specified by means of an access control list (ACL), and would be defined
for, as an example, all User Datagram Protocol (UDP) packets or all packets destined to a particular
subnetwork.
The network service is a forwarding mechanism that defines how packets are forwarded or received for
a given session. Flow in the ISG software refers to a session’s data stream as it has been identified by a
classifier. The classifier categorizes data packets based on attributes of that packet, and classifiers are
evaluated in a deterministic manner that ensures that a packet is assigned to exactly one category.
a given session. Flow in the ISG software refers to a session’s data stream as it has been identified by a
classifier. The classifier categorizes data packets based on attributes of that packet, and classifiers are
evaluated in a deterministic manner that ensures that a packet is assigned to exactly one category.
The result of configuring an ISG is a collection of powerful and dynamic policies that can be applied to
the subscriber session. The new policies are a superset of the SSG concept of a service. With the ISG
software, new subscriber rules allow you to build policies based on conditional events and by triggering
service actions. Services can be implemented within virtual routing contexts.
the subscriber session. The new policies are a superset of the SSG concept of a service. With the ISG
software, new subscriber rules allow you to build policies based on conditional events and by triggering
service actions. Services can be implemented within virtual routing contexts.
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Internet
Host object
A
B
B
A
VoD
Quake
Connection object Service object
Subscriber session
Session
feature
Traffic
classification
ACL #x
Flow
feature
Network
service
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ACL #x
ACL #x
Flow
feature
Flow
feature