Chapter 1 Product Overview
Functional Overview
To allow OIR, an address allocator with unique MAC addresses is stored in an EEPROM on the router. Each address is reserved for a specific port and slot in the router regardless of whether a port adapter resides in that slot.
The MAC addresses for port adapters are assigned to slot 3 in Cisco uBR7100 series routers, not to a particular port adapter. Assigning MAC addresses to the slot and not to the port adapter allows you to remove a port adapter and insert the port adapter into other routers without causing the MAC addresses to move around the network or to be assigned to multiple devices.
Note Storing the MAC addresses for every slot in one central location means the addresses stay with the memory device on which they are stored.
Online Insertion and Removal
The modular port adapter installed in Cisco uBR7100 series routers supports OIR. This function allows you to install and replace a port adapter while the router is operating; you do not need to notify the software or shut down the system power. This provides a method that is seamless to end users on the network, maintains all routing information, and preserves sessions.
The following is a functional description of OIR for background information only; for specific procedures for installing and replacing a port adapter in a Cisco uBR7100 series router, see the configuration note that ships with each port adapter.
Each port adapter has a bus connector that connects it to the router. Each connector has a set of tiered pins in three lengths that send specific signals to the system as they make contact with the port adapter. The system assesses the signals it receives and the order in which it receives them to determine if a port adapter is being removed or inserted into the router. From these signals, the system determines whether to reinitialize a new interface or shut down a removed interface. For example, when you insert a port adapter, the longest pins make contact with the port adapter first, and the shortest pins make contact last. The system recognizes the signals and the sequence in which it receives them.
When you remove or insert a port adapter in a Cisco uBR7100 series router, the port adapter pins send signals to notify the system, which then performs as follows:
1.Rapidly scans the system for configuration changes.
2.Initializes all newly inserted port adapters, noting any removed interfaces and placing them in the administratively shutdown state.
3.Brings all previously configured interfaces on the port adapter back to the state they were in when they were removed. Any newly inserted interfaces are put in the administratively shutdown state, as if they were present (but not configured) at boot time. If a similar port adapter type is reinserted into a slot, its ports are configured and brought online up to the port count of the original port adapter.
Peripheral Component Interconnect Buses
All interfaces connect to two Peripheral Component Interconnect (PCI) buses on the router that provide a path to packet I/O memory and the network processor. Slots 1 and 3 use PCI bus 0, and slot 0 uses PCI bus 1. The maximum recommended bandwidth points on each PCI bus is 600 points.
Note Slots 2, 4, and 5 are not used in the Cisco uBR7100 series routers.
Cisco uBR7100 Series and Cisco uBR7100E Series Universal Broadband Router Hardware Installation Guide
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