3Com 3CBLSG48 User Guide - Page 221

F GLOSSARY Access Control Entries ACEs are made of the filters that determine traffic classifications. (ACE) Access Control List ACLs can limit network traffic and restrict access to certain users or (ACL) devices by checking each packet for certain IP or MAC (i.e., Layer 2) information. Address Resolution Protocol (ARP) Boot Protocol (BOOTP) ARP converts between IP addresses and MAC (i.e., hardware) addresses. ARP is used to locate the MAC address corresponding to a given IP address. This allows the switch to use IP addresses for routing decisions and the corresponding MAC addresses to forward packets from one hop to the next. BOOTP is used to provide bootup information for network devices, including IP address information, the address of the TFTP server that contains the devices system files, and the name of the boot file. Committed Information Rate (CIR) CIR is a committed rate in bits-per-second at which the carrier agrees to accept packets from the client over a virtual circuit. The packets that are sent in excess of the CIR rate, become eligible to be discarded and not delivered if the frame relay network becomes congested, and it would then be necessary to resend these discarded packets. Committed Burst Size CbS is the maximum number of bits that can be transferred over a (CbS) frame relay lilnk during some time interval. Class of Service (CoS) CoS is supported by prioritizing packets based on the required level of service, and then placing them in the appropriate output queue. Data is transmitted from the queues using weighted round-robin service to enforce priority service and prevent blockage of lower-level queues. Priority may be set according to the port default, the packet's priority bit (in the VLAN tag), TCP/UDP port number, IP Precedence bit, or DSCP priority bit.