Cisco 10000-2P2-2DC Software Configuration Manual page 366

Information about Cisco 10000 Series Router PXF Stall Monitor
PXF stall—On the LC to PXF path, shown in
•
Cobalt3 and the PXF, the PXF stalls. The stall occurs when a packet is not completely read from the
Internal Packet Memory (IPM); therefore, the entry remains in the Cobalt3 New Work Queue
(NWQ). This entry is marked as the top entry and stays there. To avoid the stall, there is a 24-bit
counter in Cobalt3 NWQ that counts the number of clock ticks outstanding for the top entry of each
Cobalt3 NWQ. When the programmable threshold is reached, an event is generated to RP that
reloads the PXF.
• Ironbus (IB) stuck pause request—On the PXF to LC path, shown in
Request error is detected by the Nickel driver. This error occurs when the LC egress data path does
not function correctly. When this error occurs the Nickel driver restarts the Iron Bus. If the error
repeats from the same LC within 4 seconds, the entire LC is reloaded.
Control path—The RP and LCs are connected on the Backplane Ethernet (BPE). Through BPE, the
•
RP monitors the condition of the LCs, using keepalives packets that are sent every second from the
LCs to RP. If the keepalives packet does not reach RP on time, the corresponding LC gets reloaded.
Figure 17-1
LC
Figure 17-2
LC
In certain cases, the PSM detects stalls due to failures in the following data flow paths:
Cisco 10000 Series Router Software Configuration Guide
17-62
Data Path - LC to PXF
Iron Bus
Vanadium/
.Barium/Nickel
10G
Data Path - PXF to LC/RP
Iron Bus
Vanadium/
.Barium/Nickel
10G
Backplane
Chapter 17 Cisco 10000 Series Router PXF Stall Monitor
Figure 17-1, if there are no packets passing between
Iron Bus
Nickel
BP
Backplane
Iron Bus
Nickel
BP
Figure 17-2, an IB Stuck Pause
SPI-DP
Cobalt3
PXF
RP
HTDP
SPI-DP
Cobalt3
BP
PXF
BP = Back pressure
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