For CCNP Switching

Hi All,

I am creating a new blog for ccnp switch Labs. I will try to upload every single lab I do there. check out


http://ccnpswitch.blogspot.com/

Regards,
vm 

keep up the heat

I need to keep up the heat. Started the STP and it works fine in little network but the FUNDA withered with big switched network. Need to work on small then to medium and then to the big network to understand the basics and then work on the major deployments. To the right is a simple network. Amber are the blocked ports I need to understand why they are amber. Once I do, I will paste my findings.

.  

Passed CCNP- but seriously not feeling happy as it was when I passed CCNA

Today I passed CCNP Routing with 953/1000.

I was little happy because during the paper I thought, I lost it. 

Came to office just to hear "was it all from dumps". Seriously, I felt all the sleepless nights, various scenarios, hours of hard-work just went in to drain.

I am feeling little better after passing it but i am still many hops away from destination.

Need to do the same work again for switching now. Downloaded the videos for switching. 

CCNP Route tomorrow

Tomorrow if everything goes right...I will give my exam...all set...few things I need to revise...lets check how it goes....will keep posted.

successor or feasible successor

I know that only successor routes appear in the routing table, but how can I tell the difference between successor and feasible successor?

R1# show ip eigrp topology
IP-EIGRP Topology Table for AS(1)/ID(172.31.16.1)

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 172.31.151.0/24, 1 successors, FD is 768
via Connected, Loopback1
P 172.31.211.0/24, 1 successors, FD is 1024
via 172.31.11.201 (1024/76, FastEthernet0/0
P 172.31.24.0/30, 1 successors, FD is 768
via 172.31.11.2 (768/512), FastEthernet0/0
via 172.31.14.2 (1024/512), Serial0/0.4

======================================

P 172.31.24.0/30, 1 successors, FD is 768
via 172.31.11.2 (FD 768/AD 512), FastEthernet0/0
via 172.31.14.2 (FD 1024/AD 512), Serial0/0.4

since 14,2's AD< FD of 11.2(512<768), it will be added as feasible successor

Trips

There were quite a few hard months for me. There were many schedules:

Iran,KSA, Dubai and now Malaysia.

Now I got to give exam may be without dumps now. It getting very late and falling behind the schedule.

LSA and Types

http://packetlife.net/blog/2008/jun/24/ospf-area-types/

successor and feasible successor of EIGRP

this example will successfully explain when a feasible successor route will be introduced in
show ip route:
      |---5-----R2--10--R3--10--|
R1-                                            -switch---->R5----n/w
     |----5-----R4----10----------|

Route 1> R1-->R4--->R5-->n/w
FD=5+10+5=20
AD=10+5=15

Route 2> R1-->R2-->R3-->R5-->n/w
FD=5+10+10+5=30
AD=10+10+5=25

Cost of Route 1 < Route 2 Hence Route 1 will be successor. Now we know that to qualify a route as a Feasible successor we need to have the AD of a feasible successor should be less than FD of a successor

so we need to compare the Route 2 AD and Route 1 FD. But we found that 25 is not less than 20. Hence there will be no feasible successor.

Hope this helps

OSPF areas

Stub area:
* filters Type 5 LSAs
* default route is inserted into routing table on all routers in Stubby area
* E1/E2 routes are removed from routing table on all routers in Stubby area
* there can only be one exit point out of this area
* no external routes cannot be learned via Stubby area and then inserted into all OSPF areas (because LSA Type 5 is filtered in Stubby area)

Totally Stubby area:
* filters Type 3, 4, 5 LSAs
* default route is inserted into routing table on all routers in Totally Stubby area
* E1/E2 routes are removed from routing table on all routers in Totally Stubby area
* IA routes are removed from routing table on all routers in Totally Stubby area
* there can only be one exit point out of this area
* no external routes cannot be learned via Totally Stubby area and then inserted into all OSPF areas (because LSA Type 5 is filtered in Stubby area)

Not So Stubby area:
* filters Type 5 LSAs but permits Type 7 LSAs to pass through NSSA and once they reach backbone area they are converted back into Type 5 LSAs
* default route is inserted into routing table on all routers in NSSA
* E1/E2 routes are removed from routing table on all routers in NSSA
* external routes can be learned via NSSA and then inserted into all OSPF areas


Not So Stubby Totally Stubby area:
* filters Type 3,4, 5 LSAs but permits Type 7 LSAs to pass through Not So Stubby Totally Stubby area and once they reach backbone area they are converted back into Type 5 LSAs
* default route is inserted into routing table on all routers in Not So Stubby Totally Stubby area
* E1/E2 routes are removed from routing table on all routers in Not So Stubby Totally Stubby area
* IA routes are removed from routing table on all routers in Not So Stubby Totally Stubby area
* external routes can be learned via Not So Stubby Totally Stubby area and then inserted into all OSPF areas

CCNP : Time to give CCNP routing

Preparing the final time for the ccnp routing exam. I will give it as soon as I come back from my KSA trip next month. In the mean time, I would revise everything. BGP took hell lot of time, but I feel more confident and comfortable now with BGP. Atleast, I know little. I will know what they are talking about the issue.

BGP Best path selection

The following process summarizes how BGP chooses the best route on a Cisco router.

1> Prefer the route with the highest weight. (The weight attribute is proprietary to Cisco and is local to the router only.)
2> If multiple routes have the same weight, prefer the route with the highest local preference
value. (The local preference is used within an autonomous system.)

3>If multiple routes have the same local preference, prefer the route that the local router originated. A locally originated route has a next hop of 0.0.0.0 in the BGP table.

4>If none of the routes were locally originated, prefer the route with the shortest autonomous system path.

5>If the autonomous system path length is the same, prefer the lowest origin code (IGP < EGP < incomplete).

6> If all origin codes are the same, prefer the path with the lowest MED. (The MED is exchanged between autonomous systems.) The MED comparison is made only if the neighboring autonomous system is the same for all routes considered, unless the bgp always-compare-med command is enabled

7>If the routes have the same MED, prefer external paths to internal paths. If synchronization is disabled and only internal paths remain, prefer the path through the closest IGP neighbor, which means that the router
prefers the shortest internal path within the autonomous system to reach the destination (the
shortest path to the BGP next hop).

8>For EBGP paths, select the oldest route to minimize the effect of routes going up and down (flapping).
9>Prefer the route with the lowest neighbor BGP router ID value.

10>If the BGP router IDs are the same, prefer the router with the lowest neighbor IP address.--->this will for sure break the tie

Example for MED BGP

R1,R2,R4 are in AS 100 and R4 is in AS 200. Consider R3 as office router having two connections to one ISP via R1 and R4. Below is the config for MED

R1
===========

!
interface Loopback1
 ip address 1.1.1.1 255.255.255.0
!
interface FastEthernet0/0
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface FastEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface Serial1/0
 ip address 192.168.12.1 255.255.255.0
 serial restart-delay 0
 no fair-queue
!
interface Serial1/1
 ip address 192.168.14.1 255.255.255.0
 serial restart-delay 0
!
interface Serial1/2
 ip address 192.168.13.1 255.255.255.0
 serial restart-delay 0
!
interface Serial1/3
 no ip address
 shutdown
 serial restart-delay 0
!        
router bgp 100
 no synchronization
 bgp log-neighbor-changes
 network 1.1.1.0 mask 255.255.255.0
 neighbor 3.3.3.3 remote-as 200
 neighbor 3.3.3.3 ebgp-multihop 2
 neighbor 192.168.12.2 remote-as 100
 neighbor 192.168.14.2 remote-as 100
 no auto-summary
!
ip http server
!
ip route 3.3.3.3 255.255.255.255 192.168.13.2
!

R2
============

!
interface Loopback1
 ip address 2.2.2.2 255.255.255.0
!
interface FastEthernet0/0
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface FastEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface Serial1/0
 ip address 192.168.12.2 255.255.255.0
 serial restart-delay 0
!
interface Serial1/1
 ip address 192.168.24.1 255.255.255.0
 serial restart-delay 0
!
interface Serial1/2
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/3
 no ip address
 shutdown
 serial restart-delay 0
!        
router bgp 100
 no synchronization
 bgp log-neighbor-changes
 network 2.2.2.0 mask 255.255.255.0
 neighbor 192.168.12.1 remote-as 100
 neighbor 192.168.24.2 remote-as 100
 no auto-summary
!

R4
=============


!
interface FastEthernet0/0
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface FastEthernet0/1
 no ip address
 shutdown
 duplex auto
 speed auto
!
interface Serial1/0
 ip address 192.168.14.2 255.255.255.0
 serial restart-delay 0
!
interface Serial1/1
 ip address 192.168.24.2 255.255.255.0
 serial restart-delay 0
!
interface Serial1/2
 ip address 192.168.34.1 255.255.255.0
 serial restart-delay 0
!
interface Serial1/3
 no ip address
 shutdown
 serial restart-delay 0
!
router bgp 100
 no synchronization
 bgp log-neighbor-changes
 neighbor 3.3.3.3 remote-as 200
 neighbor 3.3.3.3 ebgp-multihop 2
 neighbor 192.168.14.1 remote-as 100
 neighbor 192.168.24.1 remote-as 100
 no auto-summary
!
ip http server
!
ip route 3.3.3.3 255.255.255.255 192.168.34.2
!


R3
==========



!
!
interface Loopback1
 ip address 3.3.3.3 255.255.255.0
!
interface FastEthernet0/0
 ip address 10.10.10.1 255.255.255.0
 duplex auto
 speed auto
 no keepalive
!
interface FastEthernet0/1
 ip address 20.20.20.1 255.255.255.0
 duplex auto
 speed auto
 no keepalive
!
interface Serial1/0
 ip address 192.168.13.2 255.255.255.0
 serial restart-delay 0
!
interface Serial1/1
 ip address 192.168.34.2 255.255.255.0
 serial restart-delay 0
!
interface Serial1/2
 no ip address
 shutdown
 serial restart-delay 0
!
interface Serial1/3
 no ip address
 shutdown
 serial restart-delay 0
!        
router bgp 200
 no synchronization
 bgp log-neighbor-changes
 network 10.10.10.0 mask 255.255.255.0
 network 20.20.20.0 mask 255.255.255.0
 neighbor 192.168.13.1 remote-as 100
 neighbor 192.168.13.1 ebgp-multihop 2
 neighbor 192.168.13.1 update-source Loopback1
 neighbor 192.168.13.1 route-map forr2 out
 neighbor 192.168.34.1 remote-as 100
 neighbor 192.168.34.1 ebgp-multihop 2
 neighbor 192.168.34.1 update-source Loopback1
 no auto-summary
!
ip http server
!
!
!
access-list 1 permit 10.10.10.0 0.0.0.255
access-list 2 permit 20.20.20.0 0.0.0.255
!
route-map forf2 permit 20
!        
route-map forr1 permit 1
 match ip address 1
 set metric 200
!
route-map forr2 permit 20
 match ip address 2
 set metric 400
!

BGP MED Multi Exit Discriminator

    ----->R3----->
R4                             R1
    ----->R2----->

R1 is company router is AS 100 and other routers are ISP routers with AS 200

In this scenario, lets say R1 is advertising 2 networks. 10.1.0.0 and 10.2.0.0. With all defaults, R4 would choose R2  (2.2.2.2 is specified as router ID of R2 and 3.3.3.3 for R3) to reach both networks.  check the below link for best path selection.

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094431.shtml

Now with MED you can let
R4 to choose R3 to reach R1 for 10.1.0.0
&
R4 to choose R2 to reach R1 for 10.2.0.0

on router R1

router bgp 100
 no synchronization
 bgp log-neighbor-changes
 network 10.1.0.0 mask 255.255.0.0
 network 10.2.0.0 mask 255.255.0.0
 neighbor 192.168.20.2 remote-as 200
 neighbor 192.168.20.2 route-map sMEDR2 out
 neighbor 192.168.30.2 remote-as 200
 neighbor 192.168.30.2 route-map sMEDR3 out
 no auto-summary

!

access-list 2 permit 10.2.0.0 0.0.255.255
<create access list for 10.1.0.0>
!
route-map sMEDR2 permit 10
 match ip address 2
 set metric 100
!
route-map sMEDR2 permit 20
 match ip address 1
 set metric 200
!
<create further route maps and set metric as 100>

ospf commands

sh ip protocol


Router#sh ip pro
Routing Protocol is "ospf 100"
  Outgoing update filter list for all interfaces is not set
  Incoming update filter list for all interfaces is not set
  Router ID 1.1.1.1
  Number of areas in this router is 1. 1 normal 0 stub 0 nssa
  Maximum path: 4
  Routing for Networks:
    1.1.0.0 0.0.255.255 area 100
    10.0.0.0 0.255.255.255 area 100
 Reference bandwidth unit is 100 mbps
  Routing Information Sources:
    Gateway         Distance      Last Update
    2.2.2.2              110      00:00:19
  Distance: (default is 110)


sh ip ospf  or sh ip ospf process ID --->shows how many times SPF has been calculated. More the number lesser the stability of the network.


Router#sh ip ospf                                                  
 Routing Process "ospf 100" with ID 1.1.1.1
 Start time: 00:01:25.328, Time elapsed: 00:41:49.764
 Supports only single TOS(TOS0) routes
 Supports opaque LSA
 Supports Link-local Signaling (LLS)
 Supports area transit capability
 Router is not originating router-LSAs with maximum metric
 Initial SPF schedule delay 5000 msecs
 Minimum hold time between two consecutive SPFs 10000 msecs
 Maximum wait time between two consecutive SPFs 10000 msecs
 Incremental-SPF disabled
 Minimum LSA interval 5 secs
 Minimum LSA arrival 1000 msecs
 LSA group pacing timer 240 secs
 Interface flood pacing timer 33 msecs
 Retransmission pacing timer 66 msecs
 Number of external LSA 0. Checksum Sum 0x000000
 Number of opaque AS LSA 0. Checksum Sum 0x000000
 Number of DCbitless external and opaque AS LSA 0
 Number of DoNotAge external and opaque AS LSA 0
 Number of areas in this router is 1. 1 normal 0 stub 0 nssa
 Number of areas transit capable is 0
 External flood list length 0
    Area 100
        Number of interfaces in this area is 2 (1 loopback)
        Area has no authentication
        SPF algorithm last executed 00:01:20.384 ago
        SPF algorithm executed 4 times
        Area ranges are
        Number of LSA 3. Checksum Sum 0x01587C
        Number of opaque link LSA 0. Checksum Sum 0x000000
        Number of DCbitless LSA 0
        Number of indication LSA 0
        Number of DoNotAge LSA 0
        Flood list length 0



sh ip ospf database --> shows number of connected neighbors discovered by hello packets


Router#sh ip ospf database

            OSPF Router with ID (1.1.1.1) (Process ID 100)

                Router Link States (Area 100)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.1.1.1         1.1.1.1         169         0x80000004 0x0025C1 2
2.2.2.2         2.2.2.2         168         0x80000003 0x003B9F 2

                Net Link States (Area 100)

Link ID         ADV Router      Age         Seq#       Checksum
10.10.1.1       1.1.1.1         169         0x80000001 0x00F71C



sh ip ospf interface--->

 Router#sh ip ospf interface f0/0
FastEthernet0/0 is up, line protocol is up --->state of the link
  Internet Address 10.10.1.1/24, Area 100 --->interface IP and area in which the interface is
  Process ID 100, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1----> cost of the link
  Transmit Delay is 1 sec, State DR, Priority 1 -->TD is amount of time taken in sending update to the neighbor, state is DR,BDR,Waiting,DROther. Priority is another parameter in hello packet of OPSF
  Designated Router (ID) 1.1.1.1, Interface address 10.10.1.1
  No backup designated router on this network
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5--->shows hello packet varialbles
    oob-resync timeout 40
    Hello due in 00:00:02
  Supports Link-local Signaling (LLS)
  Index 2/2, flood queue length 0
  Next 0x0(0)/0x0(0)
  Last flood scan length is 0, maximum is 0
  Last flood scan time is 0 msec, maximum is 0 msec
  Neighbor Count is 0, Adjacent neighbor count is 0
  Suppress hello for 0 neighbor(s)

Sh ip ospf neigh


Router#sh ip ospf neighbor

Neighbor ID     Pri   State           Dead Time   Address         Interface
2.2.2.2           1   FULL/BDR        00:00:33    10.10.1.2       FastEthernet0/0

it shows about neighbor states and physical interface with which the neigbor is connected


Router#sh ip ospf neighbor 2.2.2.2
 Neighbor 2.2.2.2, interface address 10.10.1.2
    In the area 100 via interface FastEthernet0/0
    Neighbor priority is 1, State is FULL, 6 state changes  -----> INIT, 2 WAY, EXSTART, EXCHANGE, LOADING, FULL,DOWN,ATTEMPT
    DR is 10.10.1.1 BDR is 10.10.1.2
    Options is 0x52
    LLS Options is 0x1 (LR)
    Dead timer due in 00:00:35
    Neighbor is up for 00:12:22
    Index 1/1, retransmission queue length 0, number of retransmission 0
    First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)
    Last retransmission scan length is 0, maximum is 0
    Last retransmission scan time is 0 msec, maximum is 0 msec

OSPF LSA types

• LSA 1 (Router LSA)

Generated by all routers in an area to describe their directly attached links (Intra-area routes). These do not leave the area.

• LSA 2 (Network LSA)

Generated by the DR of a broadcast or Nonbroadcast segment to describe the neighbors connected to the segment. These do not leave the area.

• LSA 3 (Summary LSA)

Generated by the ABR to describe a route to neighbors outside the area. (Inter-area routes)

• LSA 4 (Summary LSA)

Generated by the ABR to describe a route to an ASBR to neighbors outside the area.

• LSA 5 (External LSA)

Generated by ASBR to describe routes redistributed into the area. These routes appear as E1 or E2 in the routing table. E2 (default) uses a static cost throughout the OSPF domain as it only takes the cost into account that is reported at redistribution. E1 uses a cumulative cost of the cost reported into the OSPF domain at redistribution plus the local cost to the ASBR.

• LSA 6 (Multicast LSA)

Not supported on Cisco routers.

• LSA 7 (NSSA External LSA)

Generated by an ASBR inside a NSSA to describe routes redistributed into the NSSA. LSA 7 is translated into LSA 5 as it leaves the NSSA. These routes appear as N1 or N2 in the ip routing table inside the NSSA. Much like LSA 5, N2 is a static cost while N1 is a cumulative cost that includes the cost upto the ASBR.

EIGRP interface BW command

EIGRP bandwidth control over Serial Subinterfaces

Hi All,

Lets consider a t1 link on a routers serial interface. The link is having 4 PVC. 2 are on s1/0.1 and one on s1/0.2 and one more on the s1/0.3. If i issue no command of bandwidth control, then how the EIGRP is going to use this BW for each PVC on serial S1/0.1 and on S1/0.2 or S1/0.3.

I could understand under defaults, each interface would have around (1544/3=) 515 Kbps. But how about the 2 PVC existing on the Serial S1/0.1.

Documentation ref will also be helpful.

Cheers!

Ravi

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vmiller

610 posts sinceMar 13, 2002

1. Mar 29, 2011 9:15 AM  in response to: ravindra Krishna

Re: EIGRP bandwidth control over Serial Subinterfaces

Bandwidth values for physical interfaces are set at statrup time (based

on the hardware)

for subinterfaces (logical) youset it yourself.

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ravindra Krishna

26 posts sinceOct 26, 2010

2. Apr 7, 2011 8:17 AM  in response to: vmiller

Re: EIGRP bandwidth control over Serial Subinterfaces

Hi,

As said earlier I have not specified any BW command. Please let us know how the BW is distributed on default conditions. A ref document will also be helpful.

Cheers!

Ravi

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vmiller

610 posts sinceMar 13, 2002

3. Apr 7, 2011 8:42 AM  in response to: ravindra Krishna

Re: EIGRP bandwidth control over Serial Subinterfaces

There are default bandwidth definitions for all interfaces, its nothing you set. For serial, the default is t-1 speeds

bandwidth

#

To set a bandwidth value for an interface, use the bandwidth interface configuration command. Use theno form of this command to restore the default values.

##

bandwidth kilobitsno  bandwidth

##

Syntax Description

# kilobits

# Intended bandwidth in kilobits per  second. For a full bandwidth DS3, enter the value 44736.

##

Default

#

Default bandwidth values are set during startup and can be  displayed with the EXEC command show interfaces.

http://www.cisco.com/en/US/docs/ios/11_0/router/command/reference/rinterfc.html#wp1396

Its an old reference.

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ravindra Krishna

26 posts sinceOct 26, 2010

4. Apr 8, 2011 12:04 PM  in response to: vmiller

Re: EIGRP bandwidth control over Serial Subinterfaces

Lets consider a t1 link on a routers serial interface. The link is having 4 PVC. 2 are on s1/0.1 and one on s1/0.2 and one more on the s1/0.3. If i issue no command of bandwidth control, then how the EIGRP is going to use this BW for each PVC on serial S1/0.1 and on S1/0.2 or S1/0.3.

I could understand under defaults, each interface would have around (1544/3=) 515 Kbps. But how about the 2 PVC existing on the Serial S1/0.1.

I think I got the answer:

Since, we have not specified any BW command the default is 1544so for subinterfaces with one PVC, each would you use around (1544*50%=)772Kbps for EIGRP traffic.

And for the subinterface with 2 PVC it would be round (1544*(1/2)*50%=)386 Kbps.

Hope now this is absolutely right!

Below are ref links:

http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094063.shtml#nbma