Nortel 8600 Configuration Manual

Also see for Passport 8600 Series: Reference guide Installation Product brief Installing Commissioning

Contents

Ethernet module concepts 19Note that these values include FCS bytes.The default maximum Ethernet frame size supported by the EthernetRouting Switch 8600 is 1950 bytes. The 10 Gbit/s module also supportsthis frame size. To support a jumbo frame system, set the SF/CPU MTUto 9600 bytes on the Edit, Chassis, Chassis tab. You can also use theconfig sys set mtu CLI command or the set mtu <1522|1950|9600>NNCLI command. Interface ports can pass jumbo frames by default.If a jumbo frame enters on an interface and is destined to egress a chassisinterface that does not support jumbo frames, it is gracefully dropped.MLT/LACP groups and port speedEnsure that all ports that belong to the same MLT group or LinkAggregation Control Protocol (LACP) group use the same port speed, forexample, 1 Gbit/s, even if you use autonegotiation. The software does notenforce this requirement.Clocking and 10 Gigabit EthernetTo determine whether each incoming data bit is a one or a zero, themodule must know when to sample the incoming data stream. The moduledetermines the appropriate sampling time through clocking. Ethernetmodules have internal clocks and can regenerate a clock signal from theincoming data stream.Nortel recommends internal timing, unless you have a specific requirementfor loop timing in a system, because the transmit side operates even if afailure occurs on the incoming Receive Side Signal.You can configure clocking only for 10 Gbit/s ports.For a port that uses the internal clock and directly connects to anotherport, the other side of the link can be either internal or line (loop) clocking.For a port set for line clocking, configure the other port for internal clockingto avoid a potential timing loop.By default, each 10 Gbit/s WAN port generates the transmit clock fromits own internal clock. However, a line timing option is provided forapplications that involve synchronization to SONET equipment and timinghierarchies. You must manually change clock settings from internal to linetiming.For more information about clocking and synchronization applications, seeNortel Ethernet Routing Switch 8600 Planning and Engineering — NetworkDesign (NN46205-200).Nortel Ethernet Routing Switch 8600Configuration — Ethernet ModulesNN46205-503 04.01 21 December 2009Copyright © 2008-2009 Nortel Networks. All Rights Reserved.