Conoiguri ng UBR and UBR Circuits

UBR circuits do not guarantee that all traffic sent out on an interface will necessarily be transmitte< ATM network. These circuits are generally used under two circumstances: The traffic sent across th tolerant of delay and jitter and only requires best-effort service, or there is a cost limitation preven level of service. Standard UBR circuits require only one configuration parameter, the PCR, and are PVC configuration mode using the ubrpcr command (where pcr is measured in kbps).

UBR+ circuits also allow for an MCR value, measured in kbps that allows for the support of peak ar cell rates. UBR+ is configured under PVC configuration mode using the ubr+pcr mcr command. Ex shows how the ATM UBR+ service level is used after configuring an additional 100-Mbps PVC betw< and Wilma routers. This example shows the PVC configuration from the Fred router.

Example 4-18. Adding a UBR+ PVC to the Mix

interface ATM0.5 multipoint

ip address

pvc 5/582

protocol ip broadcast

ubr+ 106000 100000

encapsulation aal5snap

You can verify this configuration by using atm show commands. Example 4-19 shows the output c pvc and show atm vc vcd commands from the Fred router.

Example 4-19. Verifying the Configuration on the Fred Router

Fred#show atm pvc

VCD / Peak Avg/Min


Interface Name VPI VCI Type Encaps SC Kbps Kbps



0.4 1 4 482 PVC SNAP VBR 44209 9000



0.5 4 5 582 PVC SNAP UBR+ 106000 100000


Fred#show atm vc 4

ATM0.5: VCD: 4, VPI: 5, VCI: 582

UBR+, PeakRate: 106000, Minimum Guaranteed Rate: 100000

AAL5-LLC/SNAP, etype:0x0, Flags: 0x20, VCmode: 0x1

OAM frequency: 0 second(s)

InARP frequency: 15 minutes(s)

InPkts: 9877, OutPkts: 9969, InBytes: 25996105, OutBytes: 26002689

InPRoc: 9877, OutPRoc: 9878, Broadcasts: 91

InFast: 0, OutFast: 0, InAS: 0, OutAS: 0

OAM cells received: 0 OAM cells sent: 0

0 0

Post a comment