Information Technology Reference
In-Depth Information
Figure16-11Typical Multichassis Multilink PPP Scenario
A
B
ISDN PRI
access
Analog
C
Digital
Router
D
Internal service
provider
E
Remote user
Stackgroup on a corporate network
In contrast to the previous figure, Figure 16-12 features an offload router. Access servers that belong to
a stack group answer calls, establish tunnels, and forward calls to a Cisco 4700 router that wins the
bidding and is the call master for all the calls. The Cisco 4700 reassembles and resequences all the
packets coming in through the stack group.
Figure16-12Multichassis Multilink PPP with an Offload Router as a Stack Group Member
A
B
ISDN PRI
access
Analog
C
Cisco 4700
Digital
Router
D
Internal service
provider
E
Remote user
Stackgroup on a corporate network
You can build stack groups using different access server, switching, and router platforms.
However, universal access servers such as the Cisco AS5200 should not be combined with
ISDN-only access servers such as the 4
x
00 platform. Because calls from the central office
are allocated in an arbitrary way, this combination could result in an analog call being
delivered to a digital-only access server, which would not be capable of handling the call.
Note
MMP support on a group of routers requires that each router be configured to support the following:
Multilink PPP
•
Stack Group Bidding Protocol (SGBP)
•
Virtual template used for cloning interface configuration to support MMP
•
