cisco switch exam questions

cisco switch exam questions

Look at the LDP neighbor on R2 : Policy Routing Policy Route Ip route 5.5.5.5 255.255.255.255 Tunnel0 Copy this value. Run IS-IS on the entire network to announce direct connection and loopback interface. MPLS TE router ID: 1.1.1.1 Take a look at the routing table for R1 : TE with Layer 2 overlay When the router receives the IIH , it will perform a series of verification actions, such as whether the length of the SystemID matches, max area address Such as LDP ID = 1.1.1.1:0 Router-id 5.5.5.5 !! activation level1 of MPLS TE Default route injection See that no R1 will adjust the cost of the direct link 10.1.12.0 to 65545 . Network 10.1.45.4 0.0.0.0 area 0 mpls traffic-eng router-id loopback0 mpls traffic-eng area 0 75000 10.1.12.2 TE Metric : Administrative weight Network 10.1.12.1 0.0.0.0 area 0 mpls traffic-eng router-id loopback0 mpls traffic-eng area 0 16 LSP tunnel is one-way End LSP ID : End LSP ID . Indicates the last LSP ID of the LSP range described in the TLV field . 17 Password: not required, none, in use Neighbor discovery is performed by means of the Hello packet of UDP . The source and destination port of this Hello packet are both UDP646 . Ip rsvp bandwidth R2 redistributed direct route 2.2.2.0 is gone, 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. . 10.1.34.4 Both are link state routing protocols, which require routers in the area to exchange link state information, and link state information is collected in the link state database. HELLO interval, HELLO multiplier and HELLO keep interval 0x80000018 0x001C01 1 75000 When forwarding,cisco switch exam questions, if the destination address is present in the area within, the direct use of L1 LSDB routes generated forward packets, if the destination address is not in the region, the use of this area nearest L1 / L2router as an outlet outside the area network, whereby May cause sub-optimal routing The ACL filters out LDP packets. This prevents LDP adjacency between R1 and R4 from being established. Let's observe the phenomenon. Network 10.1.34.3 0.0.0.0 area 0 mpls traffic-eng router-id loopback0 mpls traffic-eng area 0 Tag rewrite with Fa0/0, 10.1.12.2, tags imposed: {203} 10.1.12.2 * 0x0000000B HOP *Aug 18 09:06:02.699: 10.1.24.4 (Strict IPv4 Prefix, 8 bytes, /32) In operational contexts , a tunnel can be removed from one path and palced onto another. 101 2 RFC2966 standardized from Level2 to Level1 leaked routes Mpls traffic-eng tunnels ip rsvp bandwidth 100 i ia 5.5.5.0 [115/158] via 10.1.123.2, FastEthernet0/0 10.0.0.0/24 is subnetted, 4 subnets Router-id 5.5.5.5 *Aug 18 09:06:02.699: Controlled Load Service break bit=0 service length=0 Lost LSPs can be requested by PSNP to see an example: Mpls traffic-eng tunnels ip rsvp bandwidth AutoBandwidth RFC3209 RSVP-TE Extensions to RSVP for LSP tunnels describes the extension of MPLS TE function by RSVP protocol . 19 =250000 bytes/sec The loopback0 address space of all devices is xxxx/32 , and x is the device number. Based on the platform ( of Per-Platform ) label space of just a LDPsession , even in the LDP there are multiple redundant links between neighbors Net 49.0001.0000.0000.0002.00 Tunnel mpls traffic-eng autoroute metric absolute resolution if the configuration of R2 is changed to: Supports allocating network resources for explicit LSP tunnels R2 (config-keychain)#exit Device Internet segment 10.1.xy.0 / 24 , where xy is the device number, X small y large If this time is specified as 0 , the periodic reoptimize will be turned off in all TE tunnels on the router . Of course, you can turn off reoptimize for a single TE tunnel , the command is as follows: InLabel : - The LSP is transmitted to R2 all the way , and in R2, the pop-up label becomes an IP packet and then forwarded to R1 . R1 then forwards the IP packet to R5 and fixes it. Calculated. In the figure above, the red path is calculated by CSPF . Finally, let's complete the configuration of R1 : *Mar 1 00:00:32.763: ISIS-Upd: Important fields changed Network 10.1.45.4 0.0.0.0 area 0 10.1.23.2 Tunnel mpls traffic-eng path-option 10 explicit name R3R4 Transport addr is generally equal to LDP ID unless it is specified by hand ( mpls ldp discovery transport-address ) . Note that here (described above) there are actually three kinds of addresses: interface IP , Transport addr , LDP ID 1.1.1.1/32 BW (kbps) Remote binding: tsr: 2.2.2.2:0, tag: imp-null Fa0/0 The configuration of R1 is as follows: MPLS is a CISCO proprietary protocol, later IETF borrowed, in IETF is called Tag Switching , can be understood as both a different name when enabled, the protocol used is not the same Link Link 0x10BA Set-overload-bit Ip cef Ip router isis The routing protocol in the IP network forwards the data packet according to the minimum metric principle. *Aug 18 11:26:02.546: Interface eth 0/1 75000 No bgp default ipv4-unicast neighbor 5.5.5.5 remote-as 2345 40s , and in order to establish an adjacency relationship, the holding time of both parties must be consistent. Keep priority Network 10.1.24.4 0.0.0.0 area 0 ! 4 10.1.45.5 0 msec * 0 msec IS-IS Level-1 Link State Database: Interface fast 0/0 Ip explicit-path name R2R4 enable next-address 10.1.12.2 Fast tag rewrite with Fa0/0, 10.1.12.2, tags commit: {203} via 10.1.12.2, FastEthernet0/0, 0 dependencies 204 IS-IS Used to request complete LSP information when the database is synchronized on the broadcast link. Tunnel mpls traffic-eng record-route IS-IS support for IPv6 Value IP internal reachability information Ip cef Router isis R1(config-if)#isis authentication key-chain test level-1 R1(config-if)#isis authentication mode md5 level-1 Ip unnumbered Loopback0 Show mpls traffic-eng link-management advertisement *Aug 18 09:06:07.919: Tun Dest: 5.5.5.5 Tun ID: 0 Ext Tun ID: 1.1.1.1 *Aug 18 04:37:06.243: min unit = 0 bytes,max pkt size = 1500 bytes Mpls traffic-eng router-id loopback0 mpls traffic-eng area 0 Router(config-router)#mpls traffic-eng area x 0x0000000D Label *Aug 18 09:06:07.919: version:1 flags:0000 cksum:BFD0 ttl:255 reserved:0 length:132 Network 10.1.34.3 0.0.0.0 area 0 The PATH message carries a label request object, which is hopped and hopped from the tunnel first-end router to the tail router. Router isis Interface Interface Ethernet0/0 Show mpls ldp discovery show mpls forwarding-table Reservable Bandwidth[3]: Mpls traffic-eng router-id Loopback0 mpls traffic-eng area 0 RSVP Signalling Info: Router ospf 1 mpls ldp sync The following will be analyzed separately: 203 IS-IS router advertisements contain direct neighbors and routing information TLVs . LSP Seq Num Router-id 6.6.6.6 We started CEF on R3 . In fact, in CEF , the default load balancing method is destination-based load balancing. CEF 's Look again, now looking at the traffic with the source of 10.1.35.55 for 1.1.1.1 , we found that R3 uses another equivalent path, that is, it goes out from the F0/0 port. This is based on the meaning of the source address pair. Router ospf 1 DBD InLabel : - Then, OSI routing begins. When an ES wants to send a packet to another ES , it sends the packet to its directly connected network. AutoRoute only affects the head end of the TE tunnel. Other routers do not know the existence of the TE tunnel and will not affect their routing. Untagged Ip router isis No bgp default ipv4-unicast neighbor 5.5.5.5 remote-as 2345 R2 will immediately trigger a new LSP and clear the ATT , which causes R1 not to use R2 as the next hop for the default route. If you change the Path-selection metric to igp , the shortest path to the tunnel will ignore the configuration in the physical interface. Choose the path with the largest " minimum available bandwidth " This TLV , in this way, provides a simple and reliable mechanism for advertising hostname information. As shown in the figure below, this is an LSP message: * 10.1.123.2, from 2.2.2.2, via FastEthernet0/0 R1#show ip route TE 's policy routing is no different from traditional policy routing, and it does not change the routing table traffic forwarding based configuration policy. Interface fast0/0 R5 configuration is as follows Mpls ip 3.3.3.3 To add: In the above environment, the loopback interface cost=1 , and the cost of all other physical interfaces =10 . Then if we configure: End host. For example , the ISO CLNP workstation searched by the ES-IS protocol . Prefix The TE LSP tunnel is initiated by the head end of the tunnel. ! Except for HELLO packets based on UDP646 , other packets are based on TCP port number 646. Router# mpls traffic-eng reoptimize Redistribute connected level-1 Affinity Bit : 0x0 IGP Metric : 1 Lists the list of directly connected IP address prefixes LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL Support IP classless routing prefix (support VLSM ) *Aug 18 04:37:06.239: Tun Dest: 5.5.5.5 Tun ID: 0 Ext Tun ID: 1.1.1.1 Headend frr information: Protected tunnel ! The link between R4-R6 and R5-R6 has a bandwidth of only 20M , which obviously does not meet the requirements. Therefore, R1 will only consider the following links: Integrated IS-IS and OSPF are 20 century 80 late-defined, which is about 1988 years. OSPF actually evolved from an earlier version of IS-IS , but it uses IP as a precondition. The core concepts of OSPF , such as the proliferation of link state information, the SPF algorithm, and the use of designated routers in the broadcast link, are borrowed from the IS-IS early version. PseudoNode ( PSN ) Version/ Protocol ID extension: Value is 1 MPLS VPN Architecture CCSP Edition 203 101 // Prerequisites for advertising a label mapping message to a neighbor locally 0 kbits/sec SNPA Assume that this is an internal network of the operator, R4 is the national trunk, R2 and R3 are left to the provincial, and the provincial internal ran IS-IS to carry the routing prefix information in the Core , and as the provincial dry exit R2 , R3 The route prefix or default route of a specific national trunk is issued. We take the default route example here. Both R2 and R3 maintain the EBGP neighbor relationship with R4 . In this case, R2 is required to be upgraded and then restarted. After the restart, IS-IS converges faster than BGP . After the first convergence, R2 to the IS-IS area. Internal flooding LSP , R1 will use R2 as the next hop of some route prefix, or the next hop of the default route. However, at this time , BGP of R2 does not converge, so that R2 is reached.The data may be discarded and black holes appear.