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Cisco CRS-1 Series Carrier Routing System Getting Started Guide
Chapter 1 Getting Started on the Cisco CRS-1 Router
Logical Routers
Logical Routers
Multiple-chassis Cisco CRS-1 router systems can be partitioned into multiple, independent routers
known as logical routers (LRs). LRs are created by configuring a set of MSCs and at least two Route
Processors (RPs) to act as an independent router.
Logical routers perform routing functions in the same manner as a physical router, but share resources
with the rest of the system. For example, the applications, configurations, protocols, and routing tables
assigned to an LR belong to that LR only, but other functions such as chassis control, Stage 2 (S2) switch
fabric, and partitioning are shared with the rest of the system.
Caution Although the Cisco CRS-1 router operates as a multiple-chassis system that allows for the configuration
of multiple LRs and all their interfaces and resources, Cisco IOS XR Software Releases 2 and 3 operate
in single-chassis systems that are shipped with one default LR. In a single-chassis system, only one LR
is necessary or operable.
Hardware Overview: Single-Chassis System
Cisco IOS XR Software Release 3 supports single-chassis CRS-1 routers, which include the following:
• Up to 8 or 16 Layer-3 MSCs and physical layer interface modules (PLIM) in an 8-slot or 16-slot
chassis
• Up to 0.64 Tbps of routing capacity
• Two dedicated slots for redundant RPs
• Up to 4 or 8 switch fabric cards in an 8-slot or 16-slot chassis
Card Slots in a Cisco CRS-1 16-Slot Line Card Chassis
Each16-slot line card chassis supports a set of cards that performs the routing and management features
of the system (see Figure 1-2).