ccna 2

ccna 2

However, there may be such a problem that the LDP connection between R1 and R2 is broken for some reason, but between R1 and R2 . ISH is sent by IS to ES Tun Sender: 1.1.1.1, LSP ID: 521 [Note] If the router receives a tagged packet and the top tag cannot be found in the local LFIB , the CISCO IOS will discard it. We saw R4 assigned to the LDP label 403 with the prefix 5.5.5.5/32 in the LFIB table of R2 . Produce PoP and untag case *Aug 18 09:06:07.919: ADSPEC type 2 length 48: In front of the IP package. Then this 303 is actually the label assigned to the route of the next hop 10.1.15.0 of BGP route 5.5.5.5 . In other words, LDP does not assign labels to BGP routes, but assigns labels to the next hop (route) of BGP routes. After the above configuration is completed, there is one more unidirectional direct link to R5 on R2 . This link will directly participate in the routing calculation of R2 itself. The overall result is that there are now three straight connectors on R2 : eth0/0 , eth0/1 , tunnel0 . Looking at the above topology, we need to establish a TE tunnel between R1 and R5 . Under normal network conditions, we want the tunnel path to be R1-R2-R5 , which is an explicit specified path. In order to make the tunnel path have a backup, we can define a path-option , this path uses the dynamic setting method, let CSPF calculate it by itself, then the configuration is as above. Note that, at the moment if desired by modifying the tunnel interface ip ospf cost so as to adjust the route cost , which for autoroute be calculated characteristics associated tunnel routing interface is not valid, use the tunnel mpls traffic-eng autoroute metric commands to configure. Network 10.1.23.2 0.0.0.0 area 0 SNPA 10.1.12.2 [MPLS: Label 203 Exp 0] 200 msec 84 msec 136 msec R1 , R2 , R3 , and R4 run the LDP protocol. Record Route: NONE ! OSPF Router with ID (1.1.1.1) (Process ID 1) Network 10.1.34.3 0.0.0.0 area 0 mpls traffic-eng router-id loopback0 mpls traffic-eng area 0 0/0/0 Mpls traffic-eng tunnels ip rsvp bandwidth Tag request object Net 49.0001.0000.0000.0003.00 Mpls traffic-eng router-id loopback0 mpls traffic-eng area 0 In an actual environment, MPLS TE is often deployed only in a few core nodes . The edge node cannot sense the existence of the TE tunnel and can only select routes according to the traditional IGP . Ip address 5.5.5.5 255.255.255.0 ip router isis R1#show ip route R1#show ip route 10.1.34.3 10.1.34.4 State: Oper; Msgs sent/rcvd: 13/13; Downstream Up time: 00:04:05 Ip unnumbered Loopback0 tunnel destination 5.5.5.5 tunnel mode mpls traffic-eng !! Backup tunnel Add: The top label is replaced (exchanged) by a new label, and one or more labels are added to the upper layer of the replaced label. [Supplement] The non-pseudo-node LSP represents a router , including all ISs and LANs connected to this router . 204 Pop Label 5.5.5.5/32 0 Tu0 point2point MAC/Encaps=14/18, MRU=1500, Label Stack{304}, via Et0/1 0E00003017000E00003016108847 00130000 R1#show mpls traffic-eng tunnels protection All routers run OSPF and the entire network is interconnected. The IP plan is as shown in the figure. Loopback0 of all devices is addressed by xxxx/32 , and x is the device number. TOS 0 Metrics: 65535 Up time: 00:00:33 Alternatively, you can configure the following command on the tail router: BandwidthOverride: disabled LockDown: disabled Verbatim: disabled Pop Label IS-IS Level-1 Link State Database: 3bit experimental bits for QoS 0 kbits/sec The work of RSVP continues to work based on the sequence of this IP address. Integrated IS-IS ( IS-IS ) enables the IS-IS protocol to propagate routing information for protocols other than CLNP . R1 , R2 , R3 , and R4 run the LDP protocol. Do not elect DIS , use CSNP to trigger database synchronization after the link is established . Error notification BW (kbps) Intermediate system adjacent router Router ospf 1 Located inside the ordinary area Then analyze in detail: The first is R2 on Mpls ip interface fast1/0 The default MaxAge is 1200 seconds and ZeroAgeLifetime is 60 seconds. When the serial number of the LSP sent by an IS reaches Ip address 2.2.2.2 255.255.255.255 R1 from eth0/1 to R5 , cost=20+1=21 of this path The configuration of R5 is as follows: 0 kbits/sec Name: R1_t0 (Tunnel0) Destination: 4.4.4.4 Status: Link connected to: a Transit Network Bw[4]: Create a TE tunnel on R1 , the source is its own loopback0 , and the destination is 4.4.4.4 of R4 . Prefix adjacent router Prefix Address-family vpnv4 neighbor 2.2.2.2 activate Net 49.0001.0000.0000.0001.00 ! Checksum: 0x6FEB Length: 132 Set-overload-bit suppress interlevel redistribute connected level-1 Metric: 0 202 OSPF Router with ID (3.3.3.3) (Process ID 1) Router Link States (Area 0) Causes of LSP generation This behavior will continue until the RESV message arrives at the head end router of the TE tunnel LSP . That is, after the request is made by the head end router, the label is advertised hop by hop from the tail router to the head end router. This shows that the TE tunnel uses the downstream passive DOD label distribution. 16 Net 49.0001.0000.0000.0001.00 *Aug 18 09:06:07.919: Layer 3 protocol ID: 2048 LSR or LSAck 5.5.5.5/32 When the router initiates IIH , the circuit type in the header is set according to the configuration we have made : L1 , L2 or L1-2 . IP internal reachability information lab environment For prefix-access-list – the IP access list that selects the destinations for which the labels will be Configure on the physical interface: Or Tunnel Id O bit The NSAP address of ID49.0001 , which enables seamless, collision-free, and non-destructive reconfiguration of the router's new NSAP address. 0x00000029 Path removal In CISCO IOS , a re-optimization of a TE tunnel is done every 1 hour by default . Let's take a look at the routing table for R1 : Local label info: global/16 Admin. Weight: 1 However, in some environments, this problem with LDP sessions may never be resolved, so it may not be desirable to wait for the establishment of an IGP adjacency forever . Then you can configure the "synchronization hold time". 4.4.4.4/32 No output feature configured When you are in a LSR configured on a TE Tunnel when the LSR becomes this TE tunnel head-end LSR . Next you can specify the destination LSR of the TE Tunnel , and the restrictions it must comply with, such as the guaranteed bandwidth of the tunnel, etc. These related parameters are at the headend LSR . Bytes tag Ip address 10.1.123.1 255.255.255.0 MPLS TE of AutoRoute characteristics of the TE tunnel as a direct link participating SPF calculation (except R2 themselves) Device Internet segment 10.1.xy.0 / 24 , where xy is the device number, X small y large 1.0.0.0 0x00000026 R2 redistributed direct route 2.2.2.0 is gone,ccna 2, inter-area route is still, and R1 no longer uses R2 as the next hop of the default route. Note that the LSP sent by R2 is also overload-bit set. . If there is no PHP mechanism: 75000 MPLS TE improves the efficiency of traffic spread across the network, avoiding inadequate and overuse of links. *Aug 18 04:37:06.239: SENDER_TEMPLATE type 7 length 12: The NSAP address of ID49.0001 , which enables seamless, collision-free, and non-destructive reconfiguration of the router's new NSAP address. Link IP Address: 10.1.23.2 ! Net 49.0001.0000.0000.0002.00 *Aug 18 04:37:06.243: Shared-Explicit (SE) Route-map test permit 10 router isis LAN Priority: 64 Format: Phase V Physical Bandwidth: 100000 kbits/sec Res. Global BW: 75000 kbits/sec Res. Sub BW: 0 kbits/sec Downstream:: 4 is IPv4 . If it is 6 or IPv6 , the LSR uses this value to determine whether the message is V4 or V6 , and then selects a complex equalization algorithm according to different IP versions. ADSPEC 6bits 10.0.0.0/24 is subnetted, 4 subnets Tunnel: IS , since this is a LAN environment, DIS is elected , and each non- DIS router advertises its own adjacency with the DIS without notifying the adjacency with other physical ISs . The LSP of R3\R3 is similar, and will not be described here. Take a look at the LSP of this pseudonode : 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 ", SNPA The forwarding of IP packets in each hop router is based only on the destination address. ( NLPID 0x81 ) and IP ( 0xCC ) Modify the bandwidth UP/DOWN threshold MPLS VPN Architecture CCSP Edition Interface eth 0/0 ...... ...... Src IP addr: 10.1.12.2; Transport IP addr: 2.2.2.2 Hold time: 15 sec; Proposed local/peer: 15/15 sec Reachable via 2.2.2.0/24 *Aug 18 09:06:07.919: LABEL_REQUEST type 1 length 8 : ATT/P/OL Neighbor 10.1.24.4 remote-as 45 no auto-summary *Aug 18 11:31:44.598: As a result, the size of the LSPDB is greatly reduced. Note that the above picture is just an abstraction and simulation concept. The ABCD four routers actually have ISIS adjacencies (in IS-IS broadcast). In the network, adjacencies are formed between routers of the same level on the same network segment, including all non- DIS routers. This is different from OSPF . However , after DIS , everyone The resulting LSP volume is reduced. That is to say, although all routers on the IS-IS broadcast network form an adjacency relationship, the synchronization of the LSDB is still guaranteed by the DIS . The LSP stability and reliability has been guaranteed. The operation of the SPF algorithm is naturally faster.