為降低保護(hù)切換代價(jià)和提高故障恢復(fù)時(shí)間，提出了以光纖級(jí)P-Cycle來實(shí)現(xiàn)網(wǎng)絡(luò)保護(hù)；研究了工作路由與光纖級(jí)P-Cycle放置聯(lián)合優(yōu)化的設(shè)計(jì)問題，給出了ILP數(shù)學(xué)模型。為降低計(jì)算的復(fù)雜度，采用了一種簡(jiǎn)單有效的方法：根據(jù)跳數(shù)預(yù)先選擇工作路由候選集及環(huán)的有效性和長(zhǎng)度預(yù)先選擇P-Cycle候選集。仿真結(jié)果表明光纖級(jí)P-Cycle設(shè)計(jì)相比于波長(zhǎng)級(jí)P-Cycle設(shè)計(jì)保護(hù)切換代價(jià)大大降低。

To reduce the protection-switching cost and failure recovery time, the fiber-level P-Cycles is presented to realize network protection. The issue about the joint optimization design of the working path routes with fiber-level P-Cycle placement is further studied; and an improved ILP formulation is developed. To reduce the complexity of joint optimization problem, the simple process of pre-selecting candidate P-Cycles by the efficiency and length metric and candidate working path routes by the hop metric is used. By simulation analysis, the fiber-level P-Cycles scheme efficiently decreases the switching cost compared with the wavelength-level P-Cycles.