Netgear XCM8806 Chassis Hardware Installation Guide - Page 754

NETGEAR 8800 Chassis Switch CLI Manual hopcount Specifies the number of hops required to age out information and notify changes in the topology. The default is 20 hops, and the range is 6 to 40 hops. Default The default hop count of a BPDU is 20 hops. Usage Guidelines This command is applicable only in an MSTP environment. If your STPD has the same name as another component, for example a VLAN, NETGEAR recommends that you specify the identifying keyword as well as the name. If your STPD has a name unique only to that STPD, the keyword stpd is optional. You should not configure any STP parameters unless you have considerable knowledge and experience with STP. The default STP parameters are adequate for most networks. The range for the parameter is 6 through 40 hops. In an MSTP environment, the hop count has the same purpose as the maxage timer for 802.1D and 802.1w environments. The main responsibility of the CIST is to exchange or propagate BPDUs across regions. The switch assigns the CIST an instance ID of 0, which allows the CIST to send BPDUs for itself in addition to all of the MSTIs within an MSTP region. Inside a region, the BPDUs contain CIST records and piggybacked M-records. The CIST records contain information about the CIST, and the M-records contain information about the MSTIs. Boundary ports only exchange CIST record BPDUs. On boundary ports, only CIST record BPDUs are exchanged. In addition, if the other end is an 802.1D or 802.1w bridge, the maxage timer is used for interoperability between the protocols. Example The following command sets the hop of the MSTP STPD, STPD2, to 30 hops: configure stpd stpd2 max-hop-count 30 configure stpd mode configure stpd mode [dot1d | dot1w | mstp [cist | msti ]] Description Configures the operational mode for the specified STP domain. 754 | Chapter 17. STP Commands