CCNA Lab - Solution Rev1.0 Basic IS-IS

To limit it to one command, configure is-type level-1 under the IS-IS router process.. It will automatically activate Level 1 on all interfaces that have IS-IS configuration... This ta

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PE2 PE3

RR

10.1.1.254

10.1.1.2

10.1.1.1

10.1.1.100

10.1.1.3

ISIS LEVEL 2 ONLY

VLA

N 21

F0/1

ISIS LEV

EL 1 ON LY

ISIS L

EVEL

1 ON LY

VLAN 31

Serial0/0.101 multipoint

ISIS LEVEL 2 ONLY

Serial0/2

Task 4.1:

Task 4.2:

♦ Configure IS-IS between RR1, PE2, and PE3

♦ IS-IS AREA NET 48.0000

♦ IS-IS RR1 AREA NET 48.0000.0254.0254

♦ IS-IS Level 1 in RR1: Configure IS-IS Level 1 only for both interfaces by using a single command

The default level of IS-IS is both Level 1 and Level 2 In order to specify Level 1 only, manual configuration needs to be entered To

limit it to one command, configure is-type level-1 under the IS-IS

router process It will automatically activate Level 1 on all interfaces that have IS-IS configuration

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♦ RR1 should advertise VLAN20 and VLAN30, including the Loopback in Level 1

RR1

interface Ethernet0/0.20 description to PE2 -VLAN 20 encapsulation dot1Q 20

ip address 172.16.20.254 255.255.255.0

ip router isis

! interface Ethernet0/0.30 description to PE3 -VLAN 30 encapsulation dot1Q 30

ip address 172.16.30.254 255.255.255.0

ip router isis

! router isis net 48.0000.0254.0254.00 is-type level-1

♦ Apply best practices to advertise Loopbacks under IS-IS

As an option, you may use ip roter isis as shown in the above output However, the best practice is to use passive-interface

Loopback0 to advertise a Loopback into IS-IS

interface Loopback0

ip address 10.1.1.254 255.255.255.255

! router isis net 48.0000.0254.0254.00 is-type level-1

passive-interface Loopback0

♦ Configure RR1 such that all changes in IS-IS get sent to logging console

router isis net 48.0000.0254.0254.00 is-type level-1

area-password iementor log-adjacency-changes all passive-interface Loopback0

Info NET ID’s Swap for a reason please read questions cerfully

♦ PE2 IS-IS AREA NET 48.0000.0001.0001.00

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♦ PE3 IS-IS AREA NET 48.0000.0002.0002.00

PE2

interface Loopback0

ip address 10.1.1.2 255.255.255.255

! router isis net 48.0000.0001.0001.00 log-adjacency-changes all passive-interface Loopback0

PE3

interface Loopback0

ip address 10.1.1.3 255.255.255.255

! router isis net 48.0000.0003.0003.00 log-adjacency-changes all passive-interface Loopback0

At this point, you should be able to receive IS-IS adjacencies

Task 4.3:

♦ Configure VLAN21 and VLAN31 on PE1 such that only Level 1 updates are exchanged from PE2 and PE3

This task is asking to configure IS-IS level 1 per interface PE1

interface FastEthernet0/0 description to PE3 VLAN31

ip address 172.16.13.1 255.255.255.0

ip router isis speed 100 full-duplex isis circuit-type level-1

! interface FastEthernet0/1 description to PE2 VLAN21

ip address 172.16.12.1 255.255.255.0

ip router isis speed 100 full-duplex isis circuit-type level-1

!

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router isis net 48.0000.0002.0002.00 is-type level-1

log-adjacency-changes all

♦ Configure PE1 to have the ability to communicate mutually with Level 1 and Level 2

Under the IS-IS router process, enter the is-type level-1-2

command It will not show up in the config output because it is the default

♦ At this stage, make sure that no Level 2 gets passed to PE2 and PE3

Note that this task is not asking you to configure Level 1 and 2 per interface

♦ Make sure you can ping 10.1.1.254 (RR1), 10.1.1.2 (PE2), and 10.1.1.3 (PE3) from PE1

RR1-RACK1#sho isis neighbors System Id Type Interface IP Address State Holdtime Circuit Id PE2-RACK1 L1 Et0/0.20 172.16.20.2 UP 21 RR1-RACK1.01 PE3-RACK1 L1 Et0/0.30 172.16.30.3 UP 8 PE3-RACK1.01

PE2-RACK1#sho isis neighbors System Id Type Interface IP Address State Holdtime Circuit Id PE1-RACK1 L1 Et0/0.21 172.16.12.1 UP 22 00

RR1-RACK1 L1 Et0/0.20 172.16.20.254 UP 8 RR1-RACK1.01

PE3-RACK1#sho isis neighbors System Id Type Interface IP Address State Holdtime Circuit Id PE1-RACK1 L1 Et0/0.31 172.16.13.1 UP 27 PE3-RACK1.02 RR1-RACK1 L1 Et0/0.30 172.16.30.254 UP 28 PE3-RACK1.01

RR1-RACK1#sho ip route isis 172.16.0.0/16 is variably subnetted, 7 subnets, 2 masks

i L1 172.16.222.0/24 [115/30] via 172.16.20.2, Ethernet0/0.20 [115/30] via 172.16.30.3, Ethernet0/0.30

i L1 172.16.12.0/24 [115/20] via 172.16.20.2, Ethernet0/0.20

i L1 172.16.13.0/24 [115/20] via 172.16.30.3, Ethernet0/0.30

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10.0.0.0/32 is subnetted, 5 subnets

i L1 10.1.1.2 [115/10] via 172.16.20.2, Ethernet0/0.20

i L1 10.1.1.3 [115/10] via 172.16.30.3, Ethernet0/0.30

i L1 10.1.1.1 [115/20] via 172.16.20.2, Ethernet0/0.20 [115/20] via 172.16.30.3, Ethernet0/0.30

PE1-RACK1#ping 10.1.1.254 Type escape sequence to abort

Sending 5, 100-byte ICMP Echos to 10.1.1.254, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/4 ms PE1-RACK1#ping 10.1.1.2

Type escape sequence to abort

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms PE1-RACK1#ping 10.1.1.3

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

Task 4.4:

♦ Establish IS-IS Level 2 adjacencies on the link between PE2 and PE3 over VLAN123

♦ Apply best practices to advertise Loopbacks under IS-IS

PE2

interface Ethernet0/0.123 description to PE3 - VLAN 123 encapsulation dot1Q 123

ip address 172.16.123.2 255.255.255.0

ip router isis isis circuit-type level-2-only

! router isis net 48.0000.0001.0001.00 is-type level-1-2 Å You won’t see this line in your output

passive-interface loopback 0

PE3

interface Ethernet0/0.123 description to PE2 - VLAN 123 encapsulation dot1Q 123

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ip address 172.16.123.3 255.255.255.0

ip router isis isis circuit-type level-2-only

! router isis net 48.0000.0003.0003.00 log-adjacency-changes all is-type level-1-2 Å In config you will not see this this is default L1-L2

passive-interface loopback 0

Verify if you’ve established Level 2 adjacencies

PE2-RACK1#sho isis neighbors System Id Type Interface IP Address State Holdtime Circuit Id PE1-RACK1 L1 Et0/0.21 172.16.12.1 UP 26 00

PE3-RACK1 L2 Et0/0.123 172.16.123.3 UP 7 PE3-RACK1.03 RR1-RACK1 L1 Et0/0.20 172.16.20.254 UP 9 RR1-RACK1.01

PE3-RACK1#sho isis neighbors System Id Type Interface IP Address State Holdtime Circuit Id PE2-RACK1 L2 Et0/0.123 172.16.123.2 UP 25 PE3-RACK1.03 PE1-RACK1 L1 Et0/0.31 172.16.13.1 UP 25 PE3-RACK1.02 RR1-RACK1 L1 Et0/0.30 172.16.30.254 UP 25 PE3-RACK1.01

♦ Configure PE1 Serial0/0 to ASBR1 Serial 0/2 interface with frame-relay encapsulation; make sure to use back-to-back serial cable

PE1

interface Serial0/0 description to Inter-AS ASBR1

no ip address encapsulation frame-relay

no keepalive

ASBR2

interface Serial0/2 description to PE1-RACK1 ISIS encapsulation frame-relay

no keepalive clock rate 8000000

The concept we are testing here is equivalent to a traditional frame-relay switch The tricky part here as is in most service

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provider production world back to back Frame-Relay is used to provide multiple services So what we are testing here is common practice that you would see in a production network There is no requirement to use LMI when the PEs are back to back This allows service providers to pass MPLS and non-MPLS traffic by utilizing sub-interfaces of a single physical interface This particular task is testing you knowledge of common problems with IS-IS over frame-relay multipoint interface The default frame frame-relay behavior is to make a physical interface a multipoint interface as soon as you

apply encapsulation frame-relay This will be the case with S0/0

and S0/2 In the next section we are going to introduce some

“gotchas” and how to troubleshoot them

♦ Configure PE1 as sub-interface S0/0.100 multipoint Use the DLCI number of your choice on both routers

This is another tricky question When picking your own DLCIs you may remember that in real network environments DLCIs are often locally significant, and having different DLCI’s would not matter

In this case we use back to back frame relay which requires using the same DLCI on each side Also, because this sub-interface is

specified as multipoint you must use frame-relay map to map all

protocols that need to pass

♦ CORRECTION!!! Configure ASBR1 Serial 0/2 interface to PE1 with encapsulation frame-relay, back-to-back

♦ On ASBR1, configure using the physical interface instead of a sub-interface

ASBR1

interface Serial0/2 description to PE1-RACK1 ISIS

ip address 172.16.222.2 255.255.255.0 encapsulation frame-relay

no keepalive clock rate 8000000 frame-relay map ip 172.16.222.1 201 broadcast Å this is required to map the far end of PE1

ASBR1-RACK1#ping 172.16.222.2 Type escape sequence to abort

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Success rate is 0 percent (0/5)

ASBR1-RACK1(config)#int ser 0/2 ASBR1-RACK1(config-if)#frame-relay map ip 172.16.222.2 201 broadcast Å

this is required in order to ping your own interface

ASBR1-RACK1#ping 172.16.222.2 Type escape sequence to abort

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 4/5/8 ms ASBR1-RACK1#

*Mar 1 12:41:13.579: ICMP: echo reply sent, src 172.16.222.2, dst 172.16.222.2

*Mar 1 12:41:13.579: ICMP: echo reply rcvd, src 172.16.222.2, dst 172.16.222.2

*Mar 1 12:41:13.583: ICMP: echo reply sent, src 172.16.222.2, dst 172.16.222.2

♦ Configure all necessary frame-relay parameters to establish basic IP connectivity from PE1 to ASBR1 such that you do not depend on Inverse ARP for frame-relay interfaces on PE1 and ASBR1

PE1

interface Serial0/0.101 multipoint description to Inter-AS ASBR1 ISIS

ip address 172.16.222.1 255.255.255.0

ip router isis frame-relay map ip 172.16.222.1 201 broadcast frame-relay map ip 172.16.222.2 201 broadcast

no frame-relay inverse-arp

ASBR1

ip address 172.16.222.2 255.255.255.0 encapsulation frame-relay

no keepalive clock rate 8000000 frame-relay map ip 172.16.222.1 201 broadcast frame-relay map ip 172.16.222.2 201 broadcast

PE1-RACK1#ping 172.16.222.2 Å ASBR1

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/3/4 ms

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ASBR1-RACK1#sho frame-relay pvc PVC Statistics for interface Serial0/2 (Frame Relay DTE) Active Inactive Deleted Static Local 0 0 0 1 Switched 0 0 0 0 Unused 0 0 0 0 DLCI = 201, DLCI USAGE = LOCAL, PVC STATUS = STATIC, INTERFACE = Serial0/2

input pkts 29505 output pkts 54016 in bytes 49499339 out bytes 143592151 dropped pkts 0 in pkts dropped 0 out pkts dropped 0 out bytes dropped 0

in FECN pkts 0 in BECN pkts 0 out FECN pkts 0 out BECN pkts 0 in DE pkts 0 out DE pkts 0 out bcast pkts 48017 out bcast bytes 143214793

5 minute input rate 13000 bits/sec, 0 packets/sec

5 minute output rate 0 bits/sec, 0 packets/sec pvc create time 12:35:45, last time pvc status changed 12:35:45

♦ Establish Level 2 IS-IS adjacencies link between PE1 and ASBR1

♦ Configure all necessary components to establish IS-IS with PE1 over a multipoint interface

♦ Make sure you can ping PE1 10.1.1.1 Loopback0

ASBR1

ip address 172.16.222.2 255.255.255.0

ip router isis encapsulation frame-relay

no keepalive clock rate 8000000 isis circuit-type level-2 frame-relay map ip 172.16.222.1 201 broadcast frame-relay map ip 172.16.222.2 201 broadcast

PE1

interface Serial0/0.101 multipoint description to Inter-AS ASBR1 ISIS

ip address 172.16.222.1 255.255.255.0

ip router isis isis circuit-type level-2 frame-relay map ip 172.16.222.1 201 broadcast frame-relay map ip 172.16.222.2 201 broadcast

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PE1-RACK1#sho isis neighbors System Id Type Interface IP Address State Holdtime Circuit Id PE2-RACK1 L1 Fa0/1 172.16.12.2 UP 29 02

PE3-RACK1 L1 Fa0/0 172.16.13.3 UP 9 PE3-RACK1.02

ASBR1-RACK1#sho isis neighbors System Id Type Interface IP Address State Holdtime Circuit Id PE1-RACK1 L2 Se0/2 172.16.222.1 INIT 24 PE1-RACK1.02

Notice the INIT state instead of Up in the output above Let’s figure out what’s going on here

ASBR1-RACK1#sho isis timer Å hidden command

Hello Process Expiration Type

| 0.181 (Parent) | 0.181 L2 Hello (Serial0/2) | 21.630 Adjacency

Update Process Expiration Type

| 1.654 (Parent) | 1.654 L2 CSNP (Serial0/2) | 6.642 Ager

| 7.556 L1 CSNP (Serial0/2) | 10:56.173 (Parent)

| 10:56.173 LSP refresh (L2 0000.1001.1001.00-00) Å you see only yourself

| 18:17.840 LSP lifetime (L2 0000.1001.1001.00-00) | 59:10.454 Dynamic Hostname cleanup

ASBR1-RACK1#debug isis adj-packets

*Mar 1 12:50:56.314: ISIS-Adj: Rec L2 IIH from DLCI 201 (Serial0/2), cir type L

2, cir id 0000.0002.0002.02, length 1500

*Mar 1 12:50:56.671: ISIS-Adj: Encapsulation failed for L2 LAN IIH on Serial0/2

*Mar 1 12:51:04.432: ISIS-Adj: Rec L2 IIH from DLCI 201 (Serial0/2), cir type L

2, cir id 0000.0002.0002.02, length 1500

As you can see from the above output, there is encapsulation failure This means that IS-IS is not establishing adjacencies It occurs because ISIS depends on the CLNS protocol which is currently not mapped in our frame-relay

PE1-RACK1(config)#int ser 0/0.101

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PE1-RACK1(config-subif)#frame-relay map clns 201 broadcast

ASBR1-RACK1(config)#int ser 0/2 ASBR1-RACK1(config-if)#frame-relay map clns 201 broadcast Mar 1 12:53:19.765: %CLNS-5-ADJCHANGE: ISIS: Adjacency to PE1-RACK1 (Serial0/2

Up, new adjacency

ASBR1-RACK1#sho isis timers Å Verify again

Hello Process Expiration Type

| 2.222 (Parent) | 2.222 L2 Hello (Serial0/2) | 27.929 Adjacency

Update Process Expiration Type

| 0.848 (Parent) | 0.848 L2 CSNP (Serial0/2) | 2.668 Ager

| 4.519 L2 CSNP (Serial0/2) | 3:20.765 Dup sysID detect | 9:49.649 (Parent)

| 9:49.649 LSP lifetime (L2 0000.0254.0254.00-00) | 9:56.452 LSP lifetime (L2 0000.0001.0001.00-00) | 10:06.649 LSP lifetime (L2 0000.0003.0003.02-00) | 11:14.653 LSP lifetime (L2 0000.0254.0254.01-00) | 11:33.828 LSP refresh (L2 0000.1001.1001.00-00) | 11:37.366 LSP refresh (L2 0000.1001.1001.01-00) | 17:20.552 LSP lifetime (L2 0000.0003.0003.00-00) | 18:18.548 LSP lifetime (L2 0000.0002.0002.00-00) | 18:20.749 LSP lifetime (L2 0000.1001.1001.00-00) | 18:20.765 LSP lifetime (L2 0000.1001.1001.01-00) | 18:21.356 LSP lifetime (L2 0000.0003.0003.01-00) | 56:06.328 Dynamic Hostname cleanup

ASBR1-RACK1#sho clns neighbors System Id Interface SNPA State Holdtime Type Protocol PE1-RACK1 Se0/2 DLCI 201 Up 20 L2 IS-IS

ASBR1-RACK1#sho isis neighbors System Id Type Interface IP Address State Holdtime Circuit Id PE1-RACK1 L2 Se0/2 172.16.222.1 UP 27 ASBR1-RACK1.01

ASBR1-RACK1#sho ip route is 172.16.0.0/16 is variably subnetted, 7 subnets, 2 masks

i L2 172.16.30.0/24 [115/30] via 172.16.222.1, Serial0/2

i L2 172.16.20.0/24 [115/30] via 172.16.222.1, Serial0/2

i L2 172.16.12.0/24 [115/20] via 172.16.222.1, Serial0/2

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