IP Event Dampening

IP Event Dampening

Suppress the effects of excessive interface flapping events on routing protocols and routing tables in the network.

Works for

Connected routes

Static routes

RIP, OSPF, EIGRP, IS-IS, and BGP

HSRP

Enabling IP Event Dampening

enable

configure terminal

interface type number

dampening [half-life-period reuse-threshold] [suppress-threshold max-suppress [restart-penalty]]

end

Without arguments : default configuration parameters.

The following example configures interface dampening on Ethernet interface 0/0 and sets the half life to 30 seconds, the reuse threshold to 1500, the suppress threshold to 10000; and the maximum suppress time to 120 seconds:

interface Ethernet 0/0

 dampening 30 1500 10000 120

RIP Commands:

Allowing Unicast Updates for RIP (version 1 and 2)

Router(config-router)# neighbor ip-address

This doesn't disable broadcast/multicast updates. Combine with "passive interface xxx" 

Applying Offsets to Routing Metrics

Router(config-router)# offset-list [access-list-number | access-list-name] {in | out} offset [interface-type interface-number]

Increase incoming and outgoing metrics to routes learned via RIP. Per route (acl) and/or per interface.

Specifying a RIP Version

Router(config-router)# version {1 | 2}

To control which RIP version an interface sends:

Router(config-if)# ip rip send version 1

Router(config-if)# ip rip send version 2

Router(config-if)# ip rip send version 1 2 To control how packets received from an interface are processed:

Router(config-if)# ip rip receive version 1

Router(config-if)# ip rip receive version 2

Router(config-if)# ip rip receive version 1 2

Enabling RIP Authentication

RIP Version 1 does not support authentication. A key chain must be defined first.Router(config-if)# ip rip authentication key-chain name-of-chainRouter(config-if)# ip rip authentication mode {text | md5}

RIP Route Summarization

Interface command: ip summary-address rip
 Example:ip summary-address rip 10.1.1.0 255.255.255.0The router advertises 10.1.1.0/24 route. Advertisement of smaller routes is suppressed. Automatic summary overrides configured summary address except when:

• The configured interface summary address and the IP address of the configured interface share the same major network (the classful, nonsubnetted portion of the IP address).

AND 

• Split horizon is not enabled on the interface.

Disabling the Validation of Source IP Addresses

Router validates the source IP address of incoming RIP routing updates. If that source address is not valid, the software discards the routing update. To disable this feature (router is “off network” and you want to receive its updates): Router(config-router)# no validate-update-source

Enabling or Disabling Split Horizon

Split horizon blocks information about routes from being advertised by a router out of any interface from which that information originated.For nonbroadcast networks you may want to disable split horizon with RIP.Router(config-if)# ip split-horizonRouter(config-if)# no ip split-horizon Split horizon for Frame Relay is disabled by default. For all other encapsulations, split horizon is enabled by default.

Configuring Interpacket Delay

Software adds no delay between packets in a multiple-packet RIP update being sent. If you have a high-end router sending to a low-speed router, you might want to add such interpacket delay to RIP updates.Router(config-router)# output-delay milliseconds

Connecting RIP to on demand circuits

RIP sends information only when there has been an update to the routing database. Periodic update packets are suppressed over the interface on which this feature is enabled.Router(config)# interface serial controller-numberRouter(config-if)# ip rip triggered

PPP over Frame Relay

PPPoFR:
Uses virtual access interfaces cloned from a virtual template interface.
Works only on point-to-point (sub-)interfaces

Configuring Virtual Template Interfaces

1. Create a virtual template interface.

2. Configure the virtual template interface: enable PPP encapsulation using encapsulation ppp.

3. Enable IP addressing on the virtual template interface using the ip unnumbered interface-type/number.

IP address pool can be used to assign IP addresses, or an IP address can be assigned directly to the virtual template interface.

Example:

interface loopback0

 ip address 172.16.1.1 255.255.255.252

 !

interface Virtual-Template1

 ip unnumbered Loopback0

 no ip directed-broadcast

 ppp authentication chap

Apply the virtual template interface and configure PPP over Frame Relay

1. In interface configuration mode enable Frame Relay with the encapsulation frame-relay command.

2. Apply a virtual template with PPP encapsulation to the DLCI to which it will apply. Use the frame-relay interface-dlci dlci [ppp virtual-template-name-string] command.

Example:

interface serial 3/0

 no ip address

 encapsulation frame-relay

 !

interface serial 3/0.1 point-to-point

 frame-relay interface-dlci 101 ppp virtual-template1

 !

interface Virtual-Template1

 ip unnumbered loopback0

 ppp authentication chap

!

interface loopback 0

 ip address 172.16.1.1 255.255.255.252

Adding CHAP Authentication to PPP over Frame Relay

Example:

!

hostname R1

!

username R2 password 0 cisco

!

interface Virtual-Template1

 ip address 192.168.1.2 255.255.255.0

 ppp authentication chap

 !

interface Serial1

 no ip address

 encapsulation frame-relay

!

interface Serial1.1 point-to-point

 frame-relay interface-dlci 101 ppp Virtual-Template1

!

hostname R2

!

username R1 password 0 cisco

!

interface Virtual-Template1

 ip address 192.168.1.1 255.255.255.0

 no peer default ip address

 ppp authentication chap

!

interface Serial1

 no ip address

 encapsulation frame-relay

!

interface Serial1.1 point-to-point

 frame-relay interface-dlci 101 ppp Virtual-Template1

!

Tips:

• Works even if Virtual-Templates on each routers are on different subnets.
• It is possible to assign ip addresses from a local pool:

R5:!interface Virtual-Template1  ip unnumbered Loopback0 peer default ip address pool PPPpool!ip local pool PPPpool 10.7.7.7 10.7.7.88!
Then, Virtual-Access interfaces get IP Addresses from this pool:R5#show ip route connected      10.0.0.0/32 is subnetted, 2 subnetsC       10.7.7.8 is directly connected, Virtual-Access2C       10.7.7.9 is directly connected, Virtual-Access3     192.168.1.0/32 is subnetted, 1 subnetsC       192.168.1.1 is directly connected, Loopback0

Create a loopback Interface on MacOS

Create a loopback Interface on MacOS X:
ifconfig lo0 alias 172.16.123.1 will add an alias IP 172.16.123.1 to the loopback adapter

ifconfig lo0 -alias 172.16.123.1 will remove it

Frame-Relay Static Mapping

Static mapping:

When dynamic mapping is forbidden:

Use "frame-relay map ip broadcast" command and "no frame-relay inverse-arp"

TIP:

Broadcast keyword is effective for the DLCI. If there is more than one mapping for the same DLCI (IP1, DLCI1); (IP2, DLCI1), there is no need to add the broadcast keyword on both. Else it will send redundant broadcast on the DLCI. 

Configuration:

On the spokes:

interface Serial0/0
 ip address 183.1.123.1 255.255.255.0
 encapsulation frame-relay
 frame-relay map ip 183.1.123.2 102 broadcast
 frame-relay map ip 183.1.123.3 102
 no frame-relay inverse-arp 

On the hub:

interface Serial0/0

 ip address 183.1.123.2 255.255.255.0

 encapsulation frame-relay

 frame-relay map ip 183.1.123.1 201 broadcast

 frame-relay map ip 183.1.123.3 203 broadcast

 no frame-relay inverse-arp 

Verification:

R5#show frame-relay map 
Serial0/0 (up): ip 183.1.0.4 dlci 504(0x1F8,0x7C80), static,
              broadcast,
              CISCO, status defined, active
Serial0/0 (up): ip 183.1.0.3 dlci 513(0x201,0x8010), static,
              broadcast,
              CISCO, status defined, active

Back up and Restore Configuration Files

Automatic Backup of Configuration using the Kron Method:

Router(config)#kron policy-list SaveConfig
Router(config-kron-policy)#cli write
Router(config-kron-policy)#exit

Router(config)#kron occurrence SaveConfigSchedule at 23:00 Sun recurring
Router(config-kron-occurrence)#policy-list SaveConfig

Multi-chassis LACP

http://www.cisco.com/en/US/docs/ios/cether/configuration/guide/ce_mlacp.html