Lucent Technologies PacketStar PSAX 4500, Руководство пользователя, Страница: 128 / 722

Chapter 3 System Features
Multiservice Media Gateway Software Features
3-60 255-700-239
PacketStar
®
PSAX 4500 Multiservice Media Gateway User Guide , Issue 2 Release 8.0.0
into IP datagrams and is forwarded in the same manner as ingress IP traffic.
The key differences between this and other IP switches is support for the fol-
lowing:
•
Virtual routing
• Service quality through the use of ATM service level mapping
The "virtual router" aspect of this device (Figure 3-18) arises from its ability
to form groupings of IP network interfaces that can combine to act as sepa-
rate IP networks relative to some other grouping of IP network interfaces on
the same device. An IP network interface may be defined in a variety of
ways, depending upon physical interface type. Each grouping of IP network
interfaces which belongs to a user will behave as the interfaces belonging to a
standard IP router. The IP addresses assigned to the IP network interfaces (as
well as the underlying IP traffic through each Route Server module) may
have overlapping address space without the concern of "crosstalk" from one
VPN to the next.
Figure 3-17. Traffic Flow Description
Enterprise/Service
Provider
ATM Network
Ingress IP
Traffic
Egress IP
Traffic
Ingress ATM
Traffic
Egress ATM
Traffic
IP
Route Server Module
ATM