In an MSTP environment, the hop count has the same purpose as the maxage timer for 802.1D and 802.1w environments. The CIST hop count is used within and outside a region. The MSTI hop count is used only inside of the region. In addition, if the other end is an 802.1D or 802.1w bridge, the maxage timer is used for interoperability between the protocols.
The BPDUs use hop counts to age out information and to notify neighbors of a topology change.
To configure the hop count.
configure stpd stpd_name max-hop-count hopcount
By default, the hop count of a BPDU is 20 hops. The range is 6 to 40 hops.