Arbiter - Cisco 7000 Hardware Installation And Maintenance

Caution
it in the appropriate slot to avoid damaging the key guides or the backplane.
Figure 1-5
processors, RP and SP (or SSP)
Interface processor
Interface processor

Arbiter

The arbiter, which arbitrates traffic on the CxBus and generates the CxBus clock, is a printed circuit
board that resides on the front of the system backplane inside the front chassis compartment.
(See Figure 1-3.) The arbiter arbitrates traffic across the CxBus by prioritizing access requests from
interface processors to ensure that each request is processed and to prevent any interface processor
from jeopardizing the CxBus and interfering with the ability of the other interface processors to
access the SSP (or SP) and RP. Following is a summary of the services that the arbiter provides:
•
CxBus clock generation—Generates the 16.667-megahertz (MHz) clock and provides a private
copy of the clock to the SP (or SSP) and each interface processor.
•
CxBus arbitration—Arbitrates interface processor requests to transmit commands on the CxBus.
The arbitration is based on a round-robin priority scheme to ensure that all interface processors
have access to a known portion of the CxBus bandwidth.
•
Global lock arbitration—Arbitrates interface processor and SP (or SSP) requests for the global
lock, a synchronization primitive used to control SP (or SSP) and interface processor access to
shared data structures.
The arbiter is a field-replaceable unit (FRU) that is available for immediate onsite replacement if the
existing arbiter fails. The "Maintenance" chapter provides replacement instructions for the arbiter.
In addition, detailed, up-to-date instructions are included with all spares when they are shipped from
the factory.
When installing an RP, SP (or SSP), or interface processor, ensure that you are installing
Backplane Slot Keys
Key guides on interface
Top
Top
key guide
slots 0–5
SSP (or SSP)
RP
Rear of
processor card
Bottom
slots 0–5
SSP (or SSP)
Bottom
key guide
RP
Physical Description
Product Overview 1-23