【正文】
源的速率同步。 時(shí)鐘源( clock source) 當(dāng)使用同步連接時(shí),其他設(shè)備將時(shí)鐘調(diào)整到和它相同的設(shè)備。 T/1 允許 。 Authentication PAP and CHAP 通常在撥號(hào)連接中使用, PAP和 CHAP可以用來(lái)驗(yàn)證連接的兩端。 ? 使用 B信道進(jìn)行數(shù)據(jù)傳輸。 Frame Relay Protocols ? Local Management Interface (LMI) ? LMI消息提供了關(guān)于當(dāng)前 DLCI值,虛電路狀態(tài)等的信息。 assumes SNA header occurs after the SDLC header LAPB (Link Access Procedure Balanced) Yes None Spec assumes single configurable protocol after LAPB. Used mainly with . Cisco uses a propriedary type field to support multiprotocol traffic. LAPD (Link Access Procedure on the D Channel) No No Not used between routers. Used on D channel from router to ISDN switch for signaling. 各種點(diǎn)到點(diǎn)通信協(xié)議的不同 Protocol Error Correction Architected Type Field Other Attributes HDLC (HighLevel Data Link Control) No No Cisco’s default on serial links. Cisco uses a proprietary type field to support mulitprotocol traffic. PPP (PointtoPoint Protocol) Allows user to choose whether error correction is performed。 Telco 電信公司 4wire circuit 從電信公司來(lái)的四芯的線路,通常是兩對(duì)雙絞線。