cisco ccna exam papers

cisco ccna exam papers

Packets with the same processing mode according to the process or IP DSCP field OSP PDU 75000 0x2D6E Tunnel mpls traffic-eng path-option 10 dynamic TE can provide a solution to avoid link overload by controlling traffic or partial traffic. Let's make a comparison: The configuration of R4 is as follows: *Aug 18 11:31:44.598: *Aug 18 09:06:02.699: SENDER_TEMPLATE type 7 length 12: Ip address 2.2.2.2 255.255.255.255 Network 4.4.4.4 0.0.0.0 area 0 Ip cef *Aug 18 09:06:07.919: DBD Tib entry: 10.1.34.0/24, rev 12 Router(config-if)#tunnel mode mpls traffic-eng When using the Explicit method to establish a tunnel , you need to associate an explicit path . Therefore, the MPLS VPN environment, if we MPLS VPN Backbone inherent R1 to R5 establish a TE the Tunnel , is not Local Outgoing Prefix Bytes Label Outgoing Next Hop Label Label or Tunnel Id Switched interface Options: (No TOS-capability, DC) LS Type: Router Links 300 OSPF of LSA aging time for the 3600s , refresh interval The command to define an Explicit path is as follows: ---------- Integrated IS-IS configuration LDP discovery sources: Prefix Mpls traffic-eng tunnels mpls label range 100 199 Ip address 2.2.2.2 255.255.255.255 Link connected to: a Transit Network S1 / 0 port hung up, then R2 will no Level2 abutting relationship, that is, R2 and backbone or level2 area disconnected, Router-id 4.4.4.4 MC The routing protocol in the IP network forwards the data packet according to the minimum metric principle. If the PSNP acknowledgment is still not received after the retransmission timout , the originating router will retransmit the LSP. i ia 10.1.24.0 [115/148] via 10.1.123.2, FastEthernet0/0 description Parameter id=127, flags=0, parameter length=5 ! ! There have also been changes here. You can see the main two contents contained in it: one is the directly connected network segment of R1 , here is 10.1.123.0 and 1.1.1.0 , and the other is the direct connection of R1 . *Aug 18 09:06:02.699: Layer 3 protocol ID: 2048 Ip rsvp bandwidth 2000 This command sets the total reservable bandwidth of the interface to 2M. Tun Sender: 1.1.1.1 LSP ID: 521 Static hostname mapping In this way , when the IP packet is tagged on the border device, the TTL value in the original IP header is not copied , but a 255 value is used instead. LSR or LSAck R1#show mpls ldp neighbor Mpls traffic-eng tunnels mpls label range 400 499 By default, TE metric is used as the basis for calculating the shortest path of a TE tunnel. !! Activate IS-IS on the interface Record Route: NONE Network 10.1.12.1 0.0.0.0 area 0 UP Tunnel mpls traffic-eng record-route *Aug 18 11:31:44.598: Interface Loopback0 So we have also defined an explicit null tag to handle the scenario described above. Router-id 4.4.4.4 Interface fa0/0 ! ! The change has occurred. In the head router,cisco ccna exam papers, this will record the labels along the way. The configuration of R1 is as follows: 10.0.0.0/24 is subnetted, 3 subnets The forwarded keyword indicates that this command is valid for traffic traversing the router. The Local keyword indicates that the traffic generated locally is effective. The label that the tail router advertises to the penultimate hop router is "explicit empty label". However, if the penultimate hop router runs CISCO IOS , it will understand this in the form of an implicit null label, that is, By default, in the TE tunnel, the message sent by the penultimate router to the tail router is unlabeled (or the top label has been removed). Local tag Router(config)# mpls ldp discovery hello interval seconds The configuration of R2 is as follows: Router#show mpls traffic-eng topology router#show mpls traffic-eng tunnels ID: path option 10 [1] Interface loopback1 Let's look at the picture. If R1 to R6 want to establish a TE tunnel , which is the optimal path, and the bandwidth requirement is 30Mbps , what is the calculation process? First of all, thanks to the flooding of link state information in the zone, " OSPF or IS-IS for MPLS TE extensions ", R3.00-00 Just throw the next hop of the traffic that meets the conditions to the tunnel interface. *Aug 18 09:06:07.919: i L2 3.3.3.0 [115/20] via 10.1.34.3, Serial0/1 MPLS application The boundary of the area is on the link Therefore, in the above figure, if R5 sends an IPv4 packet to R3 , R3 can directly identify and hash the source and destination addresses of the Ipv4 header to implement load balancing. 8bit maximum 255 , usually in the labeling when it is the ordinary ip packet TTL direct copy came 0xCC ! Local binding: tag: imp-null PHP penultimate jump pop-up mechanism However, not all messages with the same label belong to one FEC , because the EXP values ​​of these messages may be different and may be performed differently, so they may belong to different FECs . It should be noted here that if a label package is received and the label is 0 , the label will be directly popped up and the data will be submitted to the FIB for searching, and there will be no loss of the search. Label tag with tag 0 , why not just remove the tag (allocate a 13 value to the next hop to let the next hop remove the tag), why keep the tag header with 0 ? This is to maintain the uniformity of network planning under certain circumstances. For example , if QoS of MPLS is deployed , the EXP field in the label package is required, and then a label is required. When QoS is implemented , the last hop must carry the exp bit. Therefore, the label cannot be ejected. You need to configure mpls ldp explicit-null. The label assigned to a specific route is 0 and passed to the LDP neighbor (such as the penultimate hop). .