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366 Chapter 10: X.25/Frame Relay Topologies
right answer--only different solutions with different trade-offs. With practice and experience,
you will become an excellent Cisco Certified Design Professional.
Hardware
Frame Relay and X.25 use the standard 60-pin serial interfaces found on most Cisco routers. In
some cases, when there is a need for many tunnels and serial interfaces on one router, a 7507
router with the VIP card might meet the need. The VIP is an interface processor for use with the
Cisco 7000 series and Cisco 7500 series routers. It installs in the available slots in your
Cisco 7000 series or 7500 series router. The VIP uses a single motherboard with up to two
port adapters. The VIP port adapters provide the individual LAN, WAN, or LAN/WAN
interface ports.
WARNING
The VIP supports online insertion and removal (OIR), which allows you to remove and replace
a VIP without first shutting down the system. Online insertion and removal maximizes router
availability by letting you add or remove VIPs during system operation; however, the system
might indicate a hardware failure if you don't follow proper procedures. Always shut down any
ports on the port adapter cards before removing VIP or port adapters.
Tunneling is processor-intensive and should be activated cautiously when implementing STUN
and XOT. Each VIP card can contain two port adapters. Each port adapter can support eight
serial ports. That equals 16 serial ports per slot on the 7507, which has five slots available to the
CCDP for ports. If one slot is used for redundant Ethernet cards, that leaves four slots of 16 port
serial interfaces, for a total of 64 available serial ports.
Increasing demand for bandwidth-intensive services and wide-area network (WAN)
connectivity requires that network administrators maximize the capacity and efficiency of
network routers. Cisco Systems' four- and eight-port serial port adapters provide network
administrators with flexible options for a broad range of port density requirements. Cisco's
four- and eight-port serial port adapters enhance network performance at a low price per port,
making them the most cost-effective solution for maximizing router efficiency.
NOTE
Even though the port adapters have their own CPU, the tunneling of IP for STUN or XOT still
has to interrupt the main RSP processor because tunnels are process-switched. CCDPs need to
know what is process-switched and what is fast-switched.
87200333.book Page 366 Wednesday, August 22, 2001 2:53 PM