JUNOS Internet Software Network Operations Guide: Hardware
The M20 router Internet Processor II ASIC forwards packets at a throughput rate of up to 20Gigabits per second (Gbps). An optional redundant switching fabric and
Routing Engine increase system availability and ensure automatic failover in case of component failure. The ASIC technology provides such packet processing as route lookups, filtering, sampling, rate limiting, load balancing, buffer management, switching, and encapsulation and de-encapsulation of IP services.
M20 Router Components
Table 6 lists the major M20 router components and characteristics.
Table 6: M20 Router Major Hardware Components
Component
Cooling system
Craft interface
FPC
PIC
Power supply
Routing Engine
SSB
Quantity Function
3 fan trays and 1 rear
Routing
Engine fan
Cools router components
1
1–4
Displays the status and allows you to perform control functions
Connects PICs to other components and houses shared memory
Provides interfaces to various network media
1–4 per
FPC
2 AC or 2
DC
1–2
1–2
Distributes needed voltages to components
Handles routing protocols and maintains routing tables
Yes
–
–
–
Yes
Yes
Performs router lookups, manages shared memory, and transfers control packets
Yes
Redundant
Field-
Replaceable
Hot-removable, hot-insertable
Hot-removable, hot-insertable
Hot-removable, hot-insertable
Hot-removable, hot-insertable
Hot-removable, hot-insertable
Hot-pluggable
Hot-pluggable
Offline
Button
–
–
Yes
–
–
Yes
–
Field-replaceable units (FRUs) are router components that can be replaced at the customer site. Replacing FRUs requires minimal router downtime. There are three types of FRUs:
!
Hot-removable and hot-insertable—You can remove and replace the component without powering down the router or interrupting the routing functions.
!
Hot-pluggable—You can remove the component without powering down the router, but routing functions are interrupted until the replacement is installed.
!
Requires router shutdown—You must power down the router before removing the component.
16 !
M20 Router Components
