Understanding Redundant CFEBs
Purpose
Monitor redundant CFEBs so they can provide route lookup, filtering, and switching on incoming data packets and direct outbound packets to the appropriate interface for transmission to the network.
What Are Redundant CFEBs
Two CFEBs are installed in the M10i router. The M10i router CFEB processes 16 Mpps.
The CFEB performs the following functions:
- Route lookups—Performs route lookups using the forwarding table stored in the synchronous SRAM (SSRAM).
- Shared memory management—Uniformly allocates incoming data packets throughout the router's shared memory.
- Outgoing data packets transfer—Passes data packets to the destination FIC or PIC when the data is ready to be transmitted.
- Exception and control packet transfer—Passes exception packets to the microprocessor on the CFEB, which processes almost all of them. The rest are sent to the Routing Engine for further processing. Any errors originating in the Packet Forwarding Engine and detected by the CFEB are sent to the Routing Engine using system log messages.
- (M7i router only) Built-in tunnel interface—Encapsulates arbitrary packets inside a transport protocol, providing a private, secure path through an otherwise public network.
The built-in tunnel interface on the CFEB is configured the same way as a PIC. For information about configuring the built-in tunnel interface, see the JUNOS Network Interfaces and Class of Service Configuration Guide.
- (M7i router only) Optional Adaptive Services PIC-Integrated (ASP-I)—Provides one or more services on one PIC. See "Adaptive Services PIC-Integrated (ASP-I)" on page 11 for more information.
One or two CFEBs can be installed into the midplane from the rear of the chassis, as shown in Figure 233. Only one CFEB is active at a time; the optional second CFEB is in standby mode. By default, the CFEB in slot CFEB 0 is active. To modify the default, include the appropriate cfeb statement at the [edit chassis redundancy] hierarchy level of the configuration, as described in the section about CFEB redundancy in the JUNOS System Basics Configuration Guide.
CFEBs are hot-pluggable. Removing the standby CFEB has no effect on router function. If the active CFEB fails or is removed from the chassis, the effect depends on how many CFEBs are installed:
- If there is one CFEB, forwarding halts until the CFEB is replaced and functioning again. It takes approximately one minute for the replaced CFEB to boot and become active. Reading in router configuration information can take additional time, depending on the complexity of the configuration.
- If there are two CFEBs, forwarding halts while the standby CFEB boots and becomes active, which takes approximately one minute. Synchronizing router configuration information can take additional time, depending on the complexity of the configuration.