User`s guide

130 XSR User’s Guide
Interconnecting via Frame Relay Network Chapter 7
Configuring Frame Relay
Interconnecting via Frame Relay Network
The following typical application uses Frame Relay to link remote branches to
the corporate network at the central sites via a Frame Relay network.
Figure 16 Branch/Central Frame Relay Topology
New York
Minneapolis
Frame Relay
Houston
Chicago
Memphis
Frame Relay switch combines DLCIs from various
remote branch sites at 56 kbps into a single high
speed Frame Relay T1 interface with a large
number of DLCIs at the central sites.
Central Sites
Branch Sites
High speed FR link (clear channel T1/E1
links, may be channelized or fractional T3)
Many DLCIs per link
May use sub-interfaces to connect to
multiple subnets, each spanning multiple
remote sites
Link to many remote sites, may use FR
QoS templates to address different remote
sites
IP traffic requires prioritization,
bandwidth allocation
Backup solutions: separate central sites
via dial- in modem pools or ISDN
BRI/PRI with PPP, or via encrypted
tunnels over the Internet
Medium speed FR links (32 - 128 kbps)
1-4 DLCIs linking one or more central sites on
different subnets
All DLCIs share characteristics (CIR, Bc, Be)
IP traffic requires traffic prioritization,
bandwidth allocation
Backup FR link using dial-up (ISDN or dialed
modem) PPP connections or encrypted tunnel
via Internet
Boston
Network
Toronto