Currently, when pinging any interface on Router2 with 50 packets 100bytes each from Router1, the result is 100%. Change it so the success rate is always 96%.

Assuming FastEthernet Interfaces.

Router1 - Router2

—Configure control plane policing on Router2

access-list 110 permit icmp host [Router1] host [Router2] echo

class-map ICMP

match access-group 110

policy-map ICMP

class ICMP

police rate 80 pps

control-plane

service-policy input ICMP

Then from Router1 do a ping:

ping 2.2.2.2 size 100 repeat 50

Sending 50, 100-byte ICMP Echos to 2.2.2.2, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!.!!
Success rate is 96 percent (48/50), round-trip min/avg/max = 1/3/9 ms

Enjoy!

Before you go crazy trying to troubleshoot this problem, check this:

1. Check to see if there is a switch in between your IPv6 routers, make sure this switch supports IPv6! if there is a switch in between, try disabling mld snooping or ipv6 routing all together and see if it fixes the problem.

2. Setup the interfaces as non-broadcast and do neighbor statements to the link-local bypassing the Ipv6 multicast for OSPF.

3. If you changed the IPv6 OSPF router-id. Make sure you remove the OSPF process totally, clearing may not help. Then clear out the neighbor OSPF process so that neighbors accept new Router-id and do not have stale information. Check this by doing # show ipv6 ospf database

This is what I had to do to maintain stability.

Cheers!

Network Topology:

RouterA - RouterB - RouterC

First lets lets create an IP SLA to monitor RouterC from RouterA.

# ip sla monitor 1
# type echo protocol ipIcmpEcho 3.3.3.3
# timeout 2000
# frequency 5
# ip sla monitor schedule 1 life forever start-time now

Lets setup tracking for this IP SLA

# track 1 rtr 1

Now lets create a dummy route and make sure it is entered into the routing table if the IP SLA succeeds.

# ip route 12.12.12.12 255.255.255.255 null0 track 1

Lets create a prefix-list that matches this route

# ip prefix-list PR_CHECK_STATIC permit 12.12.12.12/32

Next we create a Route-map that looks for this static route in the routing table.

# route-map RM_CHECK_STATIC

# match ip address prefix-list PR_CHECK_STATIC

Lastly we apply it to our IGP Router process and originate a default route

# default-information originate route-map RM_CHECK_STATIC

Done!

Basically, if the IP SLA fails, then the route is never entered into the routing tables which causes the route-map to fail with the prefix lookup and the end result being that no default route is advertised into the network.

PEs have several other duties as well, all geared toward the issue of learning customer routes and keeping track of which routes belong to which customers. PEs exchange routes with the connected CE routers from various customers, using either EBGP, RIP-2, OSPF, or EIGRP, noting which routes are learned from which customers. To keep track of the possibly overlapping prefixes, PE routers do not put the routes in the normal IP routing table—instead, PEs store those routes in separate per-customer routing tables, called VRFs. Then the PEs use IBGP to exchange these customer routes with other PEs—never advertising the routes to the P routers.

Both ASBR1 and ASBR2 advertise defaults into the network, expecting to have the capability to route to the Internet through BGP-learned routes. In this case, ASBR2 is already up, fully converged. However, if ASBR1 reloads, when it comes back up, OSPF is likely to converge faster than BGP. As a result, ASBR1 will advertise its default route, and OSPF routers may send packets to ASBR1, but ASBR1 will end up discarding the packets until BGP converges.

Using the stub router feature on the ASBRs solves the problem by making them advertise infinite metric routes (cost 16,777,215) for any transit routes—either for a configured time period or until BGP convergence is complete. To do so, under router ospf, the ASBRs would use either the maxmetric router-lsa on-startup announce-time command or the max-metric router-lsa on-startup wait-for-bgp command. With the first version, the actual time period (in seconds) can be set. With the second, OSPF waits until BGP signals that convergence is complete or until 10 minutes pass, whichever comes first.

Simply enable frame-relay switching on your router.

# frame-relay switching

Then enable the ports for frame-relay

# int ser1/0

# encapsulation frame-relay

# int ser1/1

# encapsulation frame-relay

We need to specify these ports to be DCE even though they may be DTE interfaces.

# int ser1/0

# frame-relay intf-type dce

# int ser1/1

# frame-relay intf-type dce

Now we have two options. We can use the old school route method or the modern connect method.

Old School: under interface

# int ser1/0

# frame-relay route 100 interface serial1/1 200

# int ser1/1

# frame-relay route 200 interface serial1/0 100

Modern: Global config

# connect custA_custB serial1/0 100 serial1/1 200

As you can see the modern “connect” method is much simpler and uses less config. And don’t forget to put in the clock-rate if they are indeed DCE interfaces.

Cheers.

String matching—A string of characters in the regular expression matches any equivalent substring in the autonomous system path; 29 has three matches in | 210 291 1296 29 |, for example.

String matching alternatives—The pipe symbol (|) means “or.”

String matching ranges and wildcards—Brackets ([ ]) can be used for ranges, and the period (.) can match any single character.

String matching delimiters—The caret (^) matches the beginning of string, the dollar sign ($) matches the end of the string, and an underscore (_) matches any delimiters.

String matching grouping—Parentheses can group smaller expressions into larger expressions.

String matching special characters—You can use the backslash (\) to remove the special meaning of the character that follows.

String matching repeating operators—An asterisk (*) means the expression preceding repeats zero or more times, a question mark (?) means the expression preceding repeats zero or one time, and a plus sign (+) means the expression preceding repeats one or more times.

_200_ - All routes going through autonomous system 200
^200$ - Directly connected to autonomous system 200
_200$ - Originated in autonomous system 200
^200_. - Networks behind autonomous system 200
^[0-9]+$ - Autonomous system paths one autonomous system long
^([0-9]+)(_\1)*$ - Networks originating in the neighbor autonomous system
^$ - Networks originated in local autonomous system
.* - Matches everything

We want to set the DE on all IP Precedence routine and priority traffic exiting serial0/0/0 on DLCI 202

—Match the traffic in an ACL

# access-list 101 permit ip any any precedence 0

# access-list 101 permit ip any any precedence 1

—Create a Discard Eligible list

# frame-relay de-list 1 protocol ip list 101

—Apply this list to the Frame-Relay interface on DLCI 200

# int ser0/0/0

# frame-relay de-group 1 202

1. Use the bandwidth command to change the metric for an interface.

2. Use the cost command to change the metric for an interface.

3. Filter out the route from an advertising router. First create an ACL to match the advertising neighbor. Secondly, create an ACL to match the route in question. Thirdly, match the “ip next-hop” ACL of the neighbor and match the ACL of the route. Lastly, apply this route-map with a distribute-list inbound.

Easy huh?

# service sequence-numbers

This way you can more easily keep track of when and where events have occurred on your Cisco routers & switches. This is a very useful command for logging to syslog server. Its a must use!