all in one cisco ccie lab study guide second edition phần 3 pptx

RouterB Frame Relay DTE no frame−relay inverse−arp ← Disable Frame Relay inverse ARP support on this interface frame−relay lmi−type ansi Notice that RouterA and RouterB both have the st

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input pkts 5 output pkts 5 in bytes 520

out bytes 520 dropped pkts 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

pvc create time 00:39:19, last time pvc status changed 00:39:19

Now let's issue an extended ping with 10 ping packtets sent, each ping packet being 500 bytes

Sweep range of sizes [n]:

Type escape sequence to abort.

Sending 10, 500−byte ICMP Echos to 192.1.1.1, timeout is 2 seconds:

!!!!!!!!!!

Success rate is 100 percent (10/10), round−trip min/avg/max = 256/257/260 ms

The show frame pvc command will now show 15 input and output packets This is 10 more that the last time

we examined the values Remember that our extended ping was 10 packets Notice that the command outputshows no input or output DE packets

RouterB#sh frame pvc

PVC Statistics for interface Serial0/0 (Frame Relay DTE)

DLCI = 200, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0

input pkts 15 output pkts 15 in bytes 5560

in DE pkts 0 out DE pkts 0

Now let's do another extended ping Ping the far−end address of RouterA at 192.1.1.1 This time we will use adatagram size of 512 bytes

Sweep range of sizes [n]:

!!!!!!!!!!

Now type the show frame pvc command Notice that our input and output packets have increased by 10, from

15 to 25 Also notice that we now have 10 output DE packets This occurred because we exceeded our

512−byte limit for non−DE frames going out of the router

input pkts 25 output pkts 25 in bytes 10720

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in DE pkts 0 out DE pkts 10

The following analyzer trace shows what a frame looks like that has its DE bit set

Port A DTE ID=54, 01/25/99, 16:19:25.718925

Length=106, Good FCS

FRAME RELAY PROTOCOL

DLCI_msb 06h DLCI_lsb 4h

DLCI 100

CR 0

EA 0

FECN 0

BECN 0

DE 1 EA 1

NLPID − NETWORK LEVEL PROTOCOL ID Ethertype DOD IP 0800h IP − INTERNET PROTOCOL Version 4

IHL (in 32 bit words) 5

Precedence Routine 0h D(elay) Normal 0 T(hroughput) Normal 0 R(eliability) Normal 0 Total Length (in octets) 100

Identification 0212h D(on't) F(ragment) No 0 M(ore) F(ragments) No 0 Fragment Offset (in 8 octets) 0

Time To Live (in seconds) 255

Protocol ICMP 01h Header Checksum 316Bh Class C Source IP Address Source Net ID 196865

Source Host ID 12

Source Addr 195.1.1.12 Class C Destination IP Address Destination Net ID 196865

Destination Host ID 13

Destination Addr 195.1.1.13 ICMP − INTERNET CONTROL MESSAGE PROTOCOL Type Echo 08h Code 00h Checksum AA4Dh ID 0004h Sequence No 23FFh Dump 00000 0000 0000 6BF1 4408 ABCD k.D

00010 ABCD ABCD ABCD ABCD ABCD

00070 ABCD FCS Good 2834h

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Lab #15: Frame Relay Map Statements

Equipment Needed

The following equipment is needed to perform this lab exercise:

Three Cisco routers, two of which must have at least one serial port, and one of which must have twoserial ports

Two Cisco DTE/DCE crossover cables If no crossover cables are available, you can make a

crossover cable by connecting a standard Cisco DTE cable to a standard Cisco DCE cable

•

Configuration Overview

This configuration will demonstrate the use of the Frame Relay map statement A Frame Relay map is usedwhen connecting to a device that does not respond to an inverse ARP request Since the device does notrespond to inverse ARP, the router cannot automatically resolve the local DLCI to the far−end IP address.Configuring a Frame Relay map statement causes the router to install a static mapping to the far−end device.This static mapping contains the local DLCI and the far−end IP address Frame Relay maps can be used formany other protocols, such as IPX

The three routers are connected as shown in Figure 4−15 Two of the routers are configured as Frame RelayDTE devices The third router is configured as a Frame Relay switch The router configured as a Frame Relayswitch is also configured to supply clock to the DTE routers This is accomplished via the use of a Cisco DCEcable and a clock rate statement in the router's configuration

Figure 4−15: Frame Relay map statements

Note Keep in mind that although a Cisco router can act as a Frame Relay switch, this feature is

typically only used in test and demonstration situations such as this lab

Note The DCE side of the V.35 crossover cables must be connected to the router

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frame−relay lmi−type ansi ← Set the LMI type to Annex D

frame−relay intf−type dce ← Set the interface type to a DCE

frame−relay route 200 interface Serial0/1 201 ← Define a PVC between S0/0 and 0/1

frame−relay lmi−type ansi

frame−relay intf−type dce

frame−relay route 201 interface Serial0/0 200

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RouterB (Frame Relay DTE)

no frame−relay inverse−arp ← Disable Frame Relay inverse ARP support on this interface

frame−relay lmi−type ansi

Notice that RouterA and RouterB both have the statement no frame−relay inverse−arp under their serial 0/0

interfaces This command will stop the router from sending out an inverse ARP request on its local DLCIs.Some networking devices do not respond to inverse ARP requests, so another way must be used to tell therouter what far−end IP address corresponds to each local DLCI

Monitoring and Testing the Configuration

Let's begin by connecting to the router FrameSwitch and verifying that it is working properly Issue the show

frame pvc command to display all DLCIs that are passing through the router.

FrameSwitch#sh frame pvc

PVC Statistics for interface Serial0/0 (Frame Relay DCE)

DLCI = 200, DLCI USAGE = SWITCHED, PVC STATUS = ACTIVE, INTERFACE = Serial0/0

Num Pkts Switched 0

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as switched, the interface being referred to as a Frame Relay DCE, and the indication of Num Pkts Switched.The PVC status should indicate Active.

Next issue the show frame route command This command will display all active PVCs that are defined on

the router

FrameSwitch#sh frame route

Input Intf Input Dlci Output Intf Output Dlci Status

Serial0/0 200 Serial0/1 201 active

We see that two DLCIs are configured on this router, 200 and 201 The Frame Relay route table can beinterpreted as follows: Any traffic coming into interface S0/0 with a DLCI of 200 will be sent out interfaceS0/1 with a DLCI of 201 Any traffic coming into interface S0/1 with a DLCI of 201 will be sent out interfaceS0/0 with a DLCI of 200 The status of both DLCIs should be active

The show interface s0/0 and show interface s0/1 commands will display the statuses of the serial interfaces

on the router Several important Frame Relay parameters are displayed by this command and are highlighted

in bold including the interface encapsulation (Frame−Relay), the LMI status (LMI up), the fact that this port isacting as a Frame Relay DCE, the LMI signaling type (ANSI Annex D), and the LMI exchange counters.FrameSwitch#sh int s 0/0

Serial0/0 is up, line protocol is up

Hardware is QUICC Serial

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255

Encapsulation FRAME−RELAY, loopback not set, keepalive set (10 sec)

LMI enq sent 0, LMI stat recvd 0, LMI upd recvd 0

LMI enq recvd 297, LMI stat sent 297, LMI upd sent 0, DCE LMI up

LMI DLCI 0 LMI type is ANSI Annex D frame relay DCE

.

FrameSwitch#sh int s 0/1

LMI DLCI 0 LMI type is ANSI Annex D frame relay DCE

.

Now let's connect to RouterA Verify that RouterA uses DLCI 200 as its local DLCI:

RouterA#sh frame pvc

DLCI = 200, DLCI USAGE = UNUSED, PVC STATUS = ACTIVE, INTERFACE = Serial0/0

Num Pkts Switched 0

Display the results of the router's inverse ARP with the show frame map command.

RouterA#sh fra map

RouterA#

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Notice how there is no output from the router This is because we have disabled inverse ARP on this router.Even though the router learns about new DLCIs from the switch, it will still not inverse ARP on these DLCIs

to learn the far−end IP address In the case of RouterA, the router will not inverse ARP on DLCI 200

Now turn on Frame Relay packet debugging on RouterA Remember that debug messages only appear on the

console If you are telneted into the router or connected to the AUX port, you will also need to issue the term

mon command.

RouterA#debug frame packet

Frame Relay packet debugging is on

Verify what debug items are enabled by typing the show debug command.

RouterA#sh debug

Frame Relay:

Frame Relay packet debugging is on

Now try to ping RouterB at its address of 192.1.1.3 The ping to 192.1.1.3 fails

RouterA#ping 192.1.1.3

*Mar 1 00:52:56: Serial0/0:Encaps failed−−no map entry link 7(IP)

*Mar 1 00:52:58: Serial0/0:Encaps failed−−no map entry link 7(IP).

Success rate is 0 percent (0/5)

Let's examine the output of the debug command The ping command attempted to send five ICMP echopackets to 192.1.1.3 Each packet that was sent generated a debug statement saying that there was an

encapsulation failure with no map entry link The router cannot send the ping packet to 192.1.1.3 because itdoes not have a Frame Relay map to 192.1.1.3

Now let's connect to RouterB Verify that there is no Frame Relay map with the show frame map command.

RouterB#sh frame map

The show frame pvc command will verify that DLCI 201 is being used as the local DLCI Remember that the

router will not inverse ARP on this DLCI, since inverse ARP has been disabled

DLCI = 201, DLCI USAGE = UNUSED, PVC STATUS = ACTIVE, INTERFACE = Serial0/0

Num Pkts Switched 0

Turn on Frame Relay packet debugging on RouterB with the debug frame packet command.

RouterB#debug frame packet

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Attempt to ping RouterA at IP address 192.1.1.1.

RouterB#ping 192.1.1.1

Notice that RouterB has the same problem as RouterA Neither router knows how to reach the far−end router.Type escape sequence to abort.

Serial0/0:Encaps failed−−no map entry link 7(IP).

Serial0/0:Encaps failed−−no map entry link 7(IP).

The problem of RouterA not being able to see RouterB and RouterB not being able to see RouterA can befixed by adding a Frame Relay map in the configurations of RouterA and RouterB Enter configuration mode

and under interface s 0/0 type the frame−relay map ip 192.1.1.1 201 command This command tells RouterB

that to reach the IP address of 192.1.1.1 it should encapsulate its Frame Relay traffic in DLCI 201 and send itout interface s 0/0

Display the current Frame Relay maps with the show frame map command Remember that most changes on

the router take effect immediately Notice how there is now a mapping between 192.1.1.1 and DLCI 201.Notice also that this map is a static map The map is static because it was manually added in the configuration.RouterB#sh fra map

Serial0/0 (up): ip 192.1.1.1 dlci 201(0xC9,0x3090), static,

CISCO, status defined, active

Now let's try to ping RouterA at 192.1.1.1 with the ping 192.1.1.1 command Before typing the ping

command, turn on Frame Relay packet debugging so that you can see the results of the ping

RouterB#debug frame packet

Serial0/0 (o): dlci 201(0x3091), pkt type 0x800(IP), datagramsize 104.

The ping was not a success None of the five ICMP echo packets sent to RouterA were returned But noticethe output of the debug trace Each of the five ICMP packets sent to RouterA were encapsulated in DLCI 201.This is correct, since we now have a Frame Relay map that associates the IP address of RouterA (192.1.1.1)with DLCI 201 Why, then, did the ping not work ? RouterB knows how to get to RouterA Why did theICMP packets not get returned ? The answer is that even though RouterB has a Frame Relay map to RouterA,RouterA does not know how to get back to RouterB When the ping is sent from RouterB to RouterA, it isbeing sent to RouterA via DLCI 201 as per the Frame Relay map But when RouterA has to send the ICMP

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packet back to RouterB, it does not know how to send it The solution is to also add a Frame Relay mapstatement to RouterA so that a return path to RouterB exists.

Connect to RouterA and go into configuration mode Enter the command frame−relay map ip 192.1.1.3 200

Display the current Frame Relay map table with the show frame map command.

RouterA#sh frame map

This map tells RouterA that to get to 192.1.1.3 (which is the address of RouterB), it must send traffic out ofinterface s 0/0 encapsulated in DLCI 200

Now try to ping RouterB from RouterA The ping is successful Both RouterA and RouterB have a definedpath to each other

!!!!!

Lab #16: Full Connectivity witha Partial PVC Mesh and

FrameRelay Map Statements

Four Cisco routers, three of which must have at least one serial port, and one of which must havethree serial ports

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communicate with RouterA, then RouterB can communicate with RouterC This does not apply with FrameRelay.

Figure 4−16: Full connectivity with partial PVC mesh

This issue poses a problem in configuring Frame Relay networks As depicted in Figure 4−16, the

configuration has only two PVCs A company purchasing PVCs from a Frame Relay provider would ideallylike to be able to communicate from RouterB to RouterC without having to purchase a third PVC betweenRouterB and RouterC

The four routers are connected as shown in Figure 4−16 Three of the routers are configured as Frame RelayDTE devices The fourth router is configured as a Frame Relay switch The router configured as a FrameRelay switch is also configured to supply clock to the DTE router This is accomplished via the use of a CiscoDCE cable and a clock rate statement in the router's configuration

clockrate 64000 ← Clock the DTE at 64,000 bps

frame−relay route 200 interface Serial0/1 200 ← Define a PVC between

interface S0/0 and S0/1

!

interface Serial0/1

no ip address

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encapsulation frame−relay

clockrate 64000

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frame pvc command to display all DLCIs that are passing through the router The PVC configuration is more

complex for this lab than for the previous labs There are now two PVCs that are configured on this router.Several items indicate that these ports are acting as Frame Relay switch ports These include the DLCI usagebeing referenced as switched, the interface being referred to as a Frame Relay DCE, and the indication ofNum Pkts Switched The PVC status should indicate Active

PVC Statistics for interface Serial0/0 (Frame Relay DCE)

Num Pkts Switched 16

Num Pkts Switched 17

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the router Four DLCIs are configured on this router RouterA is acting as a hub router All DLCIs terminate

on this router RouterB and RouterC are acting as spoke routers, each having a PVC terminating on RouterA.FrameSwitch#sh frame route

The show interface command will display the status of the serial interfaces on the router Several important

Frame Relay parameters displayed by this command are highlighted in bold, including the interface

encapsulation (Frame−Relay), the LMI status (LMI up), the fact that this port is acting as a Frame Relay DCE,the LMI signaling type (ANSI Annex D), and the LMI exchange counters

.

Let's start by connecting to RouterC Type the show frame map command to display the current Frame Relay

map

RouterC#sh frame map

Serial0/0 (up): ip 192.1.1.1 dlci 210(0xD2,0x3420), dynamic,

broadcast,, status defined, active

We see that RouterC has resolved the IP address of RouterA (192.1.1.1) via inverse ARP Notice that RouterChas not resolved the address of RouterB This is because RouterC has a PVC only to RouterA, not to RouterB

In general, a spoke router (such as RouterC) will inverse ARP to the hub router (such as RouterA) but will notinverse ARP to other spoke routers

Verify that you can ping from RouterC to RouterA:

RouterC#ping 192.1.1.1

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!!!!!

Success rate is 100 percent (5/5), round−trip min/avg/max = 56/56/56 ms

Verify that DLCI 210 is active on interface s0/0 of RouterC:

RouterC#sh frame pvc

DLCI = 210, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0

out bcast pkts 1 out bcast bytes 30

Now let's connect to RouterB The show frame map command will verify that RouterB has resolved the IP

address of RouterA via inverse ARP Again, notice that RouterB does not have a mapping to RouterC.RouterB#sh frame map

Serial0/0 (up): ip 192.1.1.1 dlci 200(0xC8,0x3080), dynamic,

Verify that you can ping RouterA from RouterB:

!!!!!

Verify that DLCI 200 is active on interface s0/0 of RouterB:

Now connect to RouterA The show frame pvc command should report two DLCIs coming into RouterA,

both assigned to interface s0/0 As we can see from Figure 4−16, one of these DLCIs connects RouterA toRouterB ( DLCI 200) and the second DLCI connects RouterA to RouterC (DLCI 210)

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The show frame map command will reveal that RouterA has resolved both of its DLCIs to a far−end IP

address DLCI 200 has been resolved to 192.1.1.3 (RouterB) and DLCI 210 has been resolved to 192.1.1.4(RouterC)

RouterA#sh fra map

Serial0/0 (up): ip 192.1.1.3 dlci 200(0xC8,0x3080), dynamic,

Verify that you can reach both RouterB and RouterC with the ping command:

!!!!!

Now let's reconnect to RouterC Verify that RouterC still has a Frame Relay map to RouterA with the show

frame map command.

Serial0/0 (up): ip 192.1.1.1 dlci 210(0xD2,0x3420), dynamic,

Enable Frame Relay packet debugging with the debug frame packet command.

RouterC#debug frame packet

Verify that our hub router (RouterA) is still reachable at IP address 192.1.1.1

!!!!!

The ping should be successful The following screen print shows what the output from the debug frame

packet command will look like Notice that the outgoing pings are sent on DLCI 210 The incoming

responses also come in on DLCI 210 RouterC knows how to reach RouterA because it has a Frame Relaymap entry to RouterA Notice that there are five outgoing packets and five incoming packets

Serial0/0(o): dlci 210(0x3421), pkt type 0x800(IP), datagramsize 104

Serial0/0(i): dlci 210(0x3421), pkt type 0x800, datagramsize 104

Serial0/0(o): dlci 210(0x3421), pkt type 0x800(IP), datagramsize 104

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Serial0/0(i): dlci 210(0x3421), pkt type 0x800, datagramsize 104

Now let's try to ping RouterB at IP address 192.1.1.3

The ping failed The output of the debug frame packet shows that RouterC does not know how to

encapsulate the ping that is destined for RouterB This is caused by RouterC not having a Frame Relaymapping to RouterB

The solution is to tell RouterC how to get to RouterB with a Frame Relay map statement Enter configuration

mode and enter the command frame−relay map ip 192.1.1.3 210 under interface s 0/0 This will tell RouterC

that if it has traffic for RouterB it should send that traffic out on DLCI 210 This will be enough to get thetraffic to RouterA RouterA then has its own Frame Relay map to RouterB, so the traffic will be able to findits destination

Verify that the new Frame Relay map has taken effect by typing the show frame map command Notice how

the map to RouterA is dynamic while the map to RouterB is static This is because the map to RouterA(192.1.1.1) was discovered via inverse ARP while the map to RouterB (192.1.1.3) was manually entered intothe RouterC's configuration

Serial0/0 (up): ip 192.1.1.3 dlci 210(0xD2,0x3420), static,

Now try to ping RouterB at IP address 192.1.1.3

Serial0/0(o): dlci 210(0x3421), pkt type 0x800(IP), datagramsize 104.

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Notice that the ping still fails The output from the debug command is now different from the first time wetried to ping 192.1.1.3 The first time we tried the ping, we had not added a static Frame Relay map to192.1.1.3 and the debug output showed encapsulation failures Now the debug shows that the router knows toencapsulate the ICMP packets in DLCI 210 Why, then, does the ping fail? The ping fails because when theping traffic gets to RouterB, RouterB does not have a path back to RouterC We must now go to RouterB andadd an equivalent Frame Relay map statement.

Connect to RouterB and display the current Frame Relay map with the show frame map command Verify

that only a single dynamic map exists to RouterA at IP address 192.1.1.1

Enter configuration mode and add the statement frame−relay map IP 192.1.1.4 200 under interface s 0/0.

This will tell RouterB that if it has traffic for 192.1.1.4 (RouterC), it should then send the traffic out on DLCI

200 Encapsulating the traffic on DLCI 200 will send it to RouterA RouterA then has a Frame Relay map toRouterC and will know how to get the traffic there

You should now be able to successfully ping RouterC (at IP address 192.1.1.4) from RouterB

!!!!!

Lab #16: Full Connectivity witha Partial PVC Mesh and

FrameRelay Map Statements

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Three Cisco DTE/DCE crossover cables If no crossover cables are available, you can make a

Note The DCE side of the V.35 crossover cables must be connected to the router

communicate with RouterA, then RouterB can communicate with RouterC This does not apply with FrameRelay

Figure 4−16: Full connectivity with partial PVC mesh

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clockrate 64000 ← Clock the DTE at 64,000 bps

frame−relay route 200 interface Serial0/1 200 ← Define a PVC between interface S0/0 and S0/1

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The show interface command will display the status of the serial interfaces on the router Several important

Frame Relay parameters displayed by this command are highlighted in bold, including the interface

encapsulation (Frame−Relay), the LMI status (LMI up), the fact that this port is acting as a Frame Relay DCE,the LMI signaling type (ANSI Annex D), and the LMI exchange counters

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We see that RouterC has resolved the IP address of RouterA (192.1.1.1) via inverse ARP Notice that RouterChas not resolved the address of RouterB This is because RouterC has a PVC only to RouterA, not to RouterB

In general, a spoke router (such as RouterC) will inverse ARP to the hub router (such as RouterA) but will notinverse ARP to other spoke routers

Verify that you can ping from RouterC to RouterA:

!!!!!

Verify that DLCI 210 is active on interface s0/0 of RouterC:

Now let's connect to RouterB The show frame map command will verify that RouterB has resolved the IP

address of RouterA via inverse ARP Again, notice that RouterB does not have a mapping to RouterC

Serial0/0 (up): ip 192.1.1.1 dlci 200(0xC8,0x3080), dynamic,

Verify that you can ping RouterA from RouterB:

!!!!!

Verify that DLCI 200 is active on interface s0/0 of RouterB:

Now connect to RouterA The show frame pvc command should report two DLCIs coming into RouterA,

both assigned to interface s0/0 As we can see from Figure 4−16, one of these DLCIs connects RouterA to

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RouterB ( DLCI 200) and the second DLCI connects RouterA to RouterC (DLCI 210).

The show frame map command will reveal that RouterA has resolved both of its DLCIs to a far−end IP

address DLCI 200 has been resolved to 192.1.1.3 (RouterB) and DLCI 210 has been resolved to 192.1.1.4(RouterC)

RouterA#sh fra map

Verify that you can reach both RouterB and RouterC with the ping command:

!!!!!

Now let's reconnect to RouterC Verify that RouterC still has a Frame Relay map to RouterA with the show

frame map command.

Serial0/0 (up): ip 192.1.1.1 dlci 210(0xD2,0x3420), dynamic,

Enable Frame Relay packet debugging with the debug frame packet command.

RouterC#debug frame packet

Verify that our hub router (RouterA) is still reachable at IP address 192.1.1.1

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