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6.4 - Network Optimization

1. 跟據下圖,哪組句子正確?(選 2 組)

R3#show pfr master traffic-class 
OER Prefix Statistics:
 Pas - Passive, Act - Active, S - Short term, L - Long term, Dly - Delay (ms),
 P - Percentage below threshold, Jit - Jitter (ms), 
 MOS - Mean Opinion Score
 Los - Packet Loss (percent/10000), Un - Unreachable (flows-per-million),
 E - Egress, I - Ingress, Bw - Bandwidth (kbps), N - Not applicable
 U - unknown, * - uncontrolled, + - control more specific, @ - active probe all
 # - Prefix monitor mode is Special, & - Blackholed Prefix
 % - Force Next-Hop, ^ - Prefix is denied

DstPrefix           Appl_ID Dscp Prot     SrcPort     DstPort SrcPrefix         
           Flags             State     Time            CurrBR  CurrI/F Protocol
         PasSDly  PasLDly   PasSUn   PasLUn  PasSLos  PasLLos      EBw      IBw
         ActSDly  ActLDly   ActSUn   ActLUn  ActSJit  ActPMOS  ActSLos  ActLLos
--------------------------------------------------------------------------------
10.20.20.0/24             N    N    N           N           N N                 
                         INPOLICY*        0          10.4.4.4 Et0/1         BGP     
              46       46        0        0    35502    35502        2        1
              43       44        0        0        N        N        N        N
  1. 發生 Out of Policy (OOP) 導致 PfR 把 10.20.20.0/24 route 到 Et0/1 的 10.4.4.4
  2. 只設定了 Passive Monitoring
  3. 只設定了 Active Monitoring
  4. 沒有發生 Out of Policy (OOP)
  5. PfR 設定使用了 mode monitor 指令,縱使發生 Out Of Policy (OOP) 也不會改變 Route

D, E

Traffic Class 的狀態為 INPOLICY 代表該 Traffic 並無超出 PfR 所設的 Threshold,即沒有發生 Out of Policy (OOP)。如果發生 Out of Policy (OOP) 狀態會變成 HOLDDOWN。要確認 PfR 正使用 Active 還是 Passive Monitoring,可查看 PasSDly、PasLDly、ActSDly 及 ActLDly 等參數,如沒開啟 Passive Monitoring,PasSDly 及 PasLDly 應顯示 N,對於 Active Monitoring 也一樣。附號 * 代表使用了 mode monitor 指令 (而不是 mode route),即只會監察而不會控制 Route。