Funky Behavior with my EIGRP IP Sumarization

PLC · ‎06-25-2015

Hi All,

I configured route summarization eigrp. When pinging the R2-destination from R1-source(two hops away) it appears I have some sort of routing loop because I drop packets. I have attached my topology. R1, R3, R2. R3 is in the middle with two interfaces one connected to R1 and the other to R2 so, I summarized in both interfaces. I appreciate your help in advance!

R1

int serial1/1

ip summary address 10.1.0.0 255.255.252.0

R3

int serial 1/1

ip summary address 10.2.0.0 255.255.252.0

!

int serial 1/0

ip summary address 10.2.0.0 255.255.252.0

R2

int s1/1

ip summary address 10.2.0.0 255.255.252.0

Mark Malone · ‎06-26-2015

Just a quick thing why are you summarizing twice same subnet on R3 , do it on only 1 of the interfaces i would chose s1/0 for summarization as the upstream router will be the 1 that receives the summarized route

PLC · ‎06-26-2015

Thanks for your response Mark! Yeah, I wasnt too sure if i need to put the summarized route on both interfaces or not but i figured I should because I wanted both routers to get the advertised summary route.

I have eigrp over serial connection if that helps. So I know this cant be a split-horizon issue..

Any other ideas?

Mark Malone · ‎06-26-2015

If you remove one of those summary from r3 do you still get drops ?

If this is a lab can you post the configs ill take a look

Are you sure about spilt horizon I thought it was just on by default for frame relay serial links have you tried it ? You can check With Show interface that would have been the next thing to check

PLC · ‎06-26-2015

Hi Mark, I am have point to point serial links with eigrp running. I dont have a lab i am just trying to get these three routers up and running optimal over p to p serial links over eigrp. since I was reading about summarized routes I thought to practice but came accross these packet losses I didnt like between r1 and r2

R1#sho run | s eigrp

ip summary-address eigrp 33 10.1.0.0 255.255.252.0 5

router eigrp 33

network 10.1.1.0 0.0.0.255

network 10.1.2.0 0.0.0.255

network 10.1.3.0 0.0.0.255

network 192.168.1.0

no auto-summary

R1#sho ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 8 subnets, 2 masks

C 10.1.3.0/24 is directly connected, Loopback2

D 10.3.0.0/22 [90/2809856] via 192.168.1.2, 04:40:37, Serial1/1

D 10.2.1.0/24 [90/2297856] via 192.168.1.2, 02:46:40, Serial1/1

C 10.1.2.0/24 is directly connected, Loopback1

D 10.2.2.0/24 [90/2297856] via 192.168.1.2, 02:46:40, Serial1/1

C 10.1.1.0/24 is directly connected, Loopback0

D 10.2.3.0/24 [90/2297856] via 192.168.1.2, 02:46:40, Serial1/1

D 10.1.0.0/22 is a summary, 04:42:39, Null0

C 192.168.1.0/24 is directly connected, Serial1/1

D 192.168.2.0/24 [90/2681856] via 192.168.1.2, 07:13:29, Serial1/1

R1#

R3#sho run | s eigrp

ip summary-address eigrp 33 10.2.0.0 255.255.252.0 5

router eigrp 33

network 10.2.1.0 0.0.0.255

network 10.2.2.0 0.0.0.255

network 10.2.3.0 0.0.0.255

network 192.168.1.0

network 192.168.2.0

no auto-summary

R3#sho ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks

D 10.2.0.0/22 is a summary, 02:49:22, Null0

D 10.3.0.0/22 [90/2297856] via 192.168.2.2, 04:44:12, Serial1/0

C 10.2.1.0/24 is directly connected, Loopback0

C 10.2.2.0/24 is directly connected, Loopback1

C 10.2.3.0/24 is directly connected, Loopback2

D 10.1.0.0/22 [90/2297856] via 192.168.1.1, 04:46:16, Serial1/1

C 192.168.1.0/24 is directly connected, Serial1/1

C 192.168.2.0/24 is directly connected, Serial1/0

R3#

R2#sho run | s eigrp

ip summary-address eigrp 33 10.3.0.0 255.255.252.0 5

router eigrp 33

network 10.3.1.0 0.0.0.255

network 10.3.2.0 0.0.0.255

network 10.3.3.0 0.0.0.255

network 192.168.2.0

no auto-summary

R2#sho ip route

Codes: C - connected, S - static, R - RIP, M - mobile, B - BGP

D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area

N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2

E1 - OSPF external type 1, E2 - OSPF external type 2

i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2

ia - IS-IS inter area, * - candidate default, U - per-user static route

o - ODR, P - periodic downloaded static route

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks

C 10.3.1.0/24 is directly connected, Loopback0

D 10.2.0.0/22 [90/2297856] via 192.168.2.1, 02:47:51, Serial1/1

D 10.3.0.0/22 is a summary, 04:41:18, Null0

C 10.3.3.0/24 is directly connected, Loopback2

C 10.3.2.0/24 is directly connected, Loopback1

D 10.1.0.0/22 [90/2809856] via 192.168.2.1, 04:43:20, Serial1/1

D 192.168.1.0/24 [90/2681856] via 192.168.2.1, 07:14:07, Serial1/1

C 192.168.2.0/24 is directly connected, Serial1/1

R2#

Mark Malone · ‎06-29-2015

Hi

i threw your config into a quick lab , strange enough as below mine works fine , what i notice is im receiving only the summary routes from R3 on r1 and r2 while you also receive the /24 addresses on r1 from r3 even though there's a summary on the interface that is if you still have the 2 summary's configured on r3 , im not dropping any traffic as below between r1 and r2 , are the 2 summary routes still there

r1#ping 10.3.2.1 re 100

Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 10.3.2.1, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (100/100), round-trip min/avg/max = 28/70/104 ms
r1#ping 10.3.3.1 re 100

Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 10.3.3.1, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (100/100), round-trip min/avg/max = 20/68/112 ms
r1#sh ip route | b Gate
Gateway of last resort is not set

     10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
D       10.2.0.0/22 [90/2297856] via 192.168.1.2, 00:04:41, Serial1/1
C       10.1.3.0/24 is directly connected, Loopback3
D       10.3.0.0/22 [90/2809856] via 192.168.1.2, 00:02:50, Serial1/1
C       10.1.2.0/24 is directly connected, Loopback2
C       10.1.1.0/24 is directly connected, Loopback1
D       10.1.0.0/22 is a summary, 00:09:43, Null0
C    192.168.1.0/24 is directly connected, Serial1/1
D    192.168.2.0/24 [90/2681856] via 192.168.1.2, 00:16:18, Serial1/1
r1##

r2#sh ip route | b Gatew
Gateway of last resort is not set

     10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
C       10.3.1.0/24 is directly connected, Loopback1
D       10.2.0.0/22 [90/2297856] via 192.168.2.1, 00:03:39, Serial1/1
D       10.3.0.0/22 is a summary, 00:01:54, Null0
C       10.3.3.0/24 is directly connected, Loopback3
C       10.3.2.0/24 is directly connected, Loopback2
D       10.1.0.0/22 [90/2809856] via 192.168.2.1, 00:08:46, Serial1/1
D    192.168.1.0/24 [90/2681856] via 192.168.2.1, 00:14:29, Serial1/1
C    192.168.2.0/24 is directly connected, Serial1/1
r2#ping 10.1.2.1 re 100

Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 10.1.2.1, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (100/100), round-trip min/avg/max = 12/57/108 ms
r2#ping 10.1.3.1 re 100

Type escape sequence to abort.
Sending 100, 100-byte ICMP Echos to 10.1.3.1, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (100/100), round-trip min/avg/max = 12/61/120 ms
r2#

r3#sh ip route | b Gat
Gateway of last resort is not set

     10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
D       10.2.0.0/22 is a summary, 00:13:40, Null0
D       10.3.0.0/22 [90/2297856] via 192.168.2.2, 00:11:49, Serial1/1
C       10.2.1.0/24 is directly connected, Loopback1
C       10.2.2.0/24 is directly connected, Loopback2
C       10.2.3.0/24 is directly connected, Loopback3
D       10.1.0.0/22 [90/2297856] via 192.168.1.1, 00:18:41, Serial1/0
C    192.168.1.0/24 is directly connected, Serial1/0
C    192.168.2.0/24 is directly connected, Serial1/1
r3#

PLC · ‎06-30-2015

Hi Mark, Thanks for the follow up. Yeah, this one is bugging me.. so where it loses packets is from R1 to R2 and vice versa. the middle router R3 i can both routers just fine. Any idea why I could be losing packets from R1 to R2? R3 pinging out of both interfaces is 100 percent successful.

Mark Malone · ‎07-01-2015

If you remove the summary routes does it stop the drops to rule that out as i was not able to replicate the problem with the config you provided using summary routes so it may be something else?

Is there anything else set under the interfaces for the interfaces involved

PLC · ‎07-01-2015

I just removed the summary routes and that worked. pings 100 percent accross all routers with no packet loss.

Before removing the summary routes here is the configurations with summary routes:

R1

interface Serial1/1

ip address 192.168.2.2 255.255.255.0

ip summary-address eigrp 33 10.1.0.0 255.255.252.0 5

serial restart-delay 0

R3

interface Serial1/0

ip address 192.168.2.1 255.255.255.0

ip summary-address eigrp 33 10.2.0.0 255.255.252.0 5

serial restart-delay 0

no fair-queue

!

interface Serial1/1

ip address 192.168.1.2 255.255.255.0

serial restart-delay 0

R2

interface Serial1/1

ip address 192.168.2.2 255.255.255.0

ip summary-address eigrp 33 10.3.0.0 255.255.252.0 5

serial restart-delay 0

PLC · ‎07-01-2015

acutally I noticed just now that the packets drop even with no summary. So the issue indeed is not with the summary route.

PLC · ‎07-01-2015

Do I need to put a clock rate somewhere?

Mark Malone · ‎07-02-2015

ok so thats confirmed then at least as i got no drops in my lab same config which is good to rule out the summarization , yes clocking is required in real world equipment not in labs usually , clocking is set on the dce side , i think from memory you can check which is dce if already connected from doing a show controllers sx/x/x it should tell your interface is dte or dce , it depends on the cable connection

Are you seeing drops under the serial interfaces incrementing when pinging , crcs,frame errors ?

PLC · ‎07-02-2015

No I dont see any counters incrementing.

Success rate is 60 percent (3/5), round-trip min/avg/max = 24/565/1528 ms

R1#sho int serial 1/1

Serial1/1 is up, line protocol is up

Hardware is M4T

Internet address is 192.168.1.1/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, crc 16, loopback not set

Keepalive set (10 sec)

Restart-Delay is 0 secs

Last input 00:00:00, output 00:00:04, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: weighted fair

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations 0/1/256 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

Available Bandwidth 1158 kilobits/sec

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

5 minute output rate 0 bits/sec, 0 packets/sec

5520 packets input, 359046 bytes, 0 no buffer

Received 1889 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

5483 packets output, 356804 bytes, 0 underruns

0 output errors, 0 collisions, 1 interface resets

0 output buffer failures, 0 output buffers swapped out

2 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up

R3#sho int serial 1/0

Serial1/0 is up, line protocol is up

Hardware is M4T

Internet address is 192.168.2.1/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, crc 16, loopback not set

Keepalive set (10 sec)

Restart-Delay is 0 secs

Last input 00:00:02, output 00:00:02, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

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

5 minute output rate 0 bits/sec, 0 packets/sec

44229 packets input, 2881229 bytes, 0 no buffer

Received 17120 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

44868 packets output, 2923804 bytes, 0 underruns

0 output errors, 0 collisions, 4 interface resets

0 output buffer failures, 0 output buffers swapped out

5 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up

R3#sho int serial 1/1

Serial1/1 is up, line protocol is up

Hardware is M4T

Internet address is 192.168.1.2/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, crc 16, loopback not set

Keepalive set (10 sec)

Restart-Delay is 0 secs

Last input 00:00:00, output 00:00:00, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: weighted fair

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations 0/1/256 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

Available Bandwidth 1158 kilobits/sec

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

5 minute output rate 0 bits/sec, 0 packets/sec

44700 packets input, 2904868 bytes, 0 no buffer

Received 17210 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

45052 packets output, 2932794 bytes, 0 underruns

0 output errors, 0 collisions, 3 interface resets

R2#sho int serial 1/1

Serial1/1 is up, line protocol is up

Hardware is M4T

Internet address is 192.168.2.2/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, crc 16, loopback not set

Keepalive set (10 sec)

Restart-Delay is 0 secs

Last input 00:00:03, output 00:00:01, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: weighted fair

Output queue: 0/1000/64/0 (size/max total/threshold/drops)

Conversations 0/1/256 (active/max active/max total)

Reserved Conversations 0/0 (allocated/max allocated)

Available Bandwidth 1158 kilobits/sec

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

5 minute output rate 0 bits/sec, 0 packets/sec

5591 packets input, 363560 bytes, 0 no buffer

Received 1914 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

5521 packets output, 359082 bytes, 0 underruns

0 output errors, 0 collisions, 1 interface resets

0 output buffer failures, 0 output buffers swapped out

2 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up

R3#sho int serial 1/0

Serial1/0 is up, line protocol is up

Hardware is M4T

Internet address is 192.168.2.1/24

MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec,

reliability 255/255, txload 1/255, rxload 1/255

Encapsulation HDLC, crc 16, loopback not set

Keepalive set (10 sec)

Restart-Delay is 0 secs

Last input 00:00:02, output 00:00:04, output hang never

Last clearing of "show interface" counters never

Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0

Queueing strategy: fifo

Output queue: 0/40 (size/max)

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

5 minute output rate 0 bits/sec, 0 packets/sec

44333 packets input, 2888380 bytes, 0 no buffer

Received 17153 broadcasts, 0 runts, 0 giants, 0 throttles

0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort

44974 packets output, 2931028 bytes, 0 underruns

0 output errors, 0 collisions, 4 interface resets

0 output buffer failures, 0 output buffers swapped out

5 carrier transitions DCD=up DSR=up DTR=up RTS=up CTS=up