Figure18.3帧中继帧 C/R:Command/response BECN:Backward explicit congestion notification EA:Extended address DE:Discard eligibility FECN:Forward explicit congestion notification DLCl:Data link connection identifier Flag Address Information FCS Flag DLCI C/R EA DLCI FECN BECN DE EA 6 bits 1 bit 1 bit 4bits 1 bit 1 bit 1 bit 1 bit 18.7 18.7 Figure 18.3 帧中继帧