pause for station identification...

let's hope narbik doesn't mind the free publicity...

R5#sh ip bgp
R5#

When redistributing between OSPF and BGP, we should review BGP’s synchronization rule which states:

An IBGP learned prefix will not be advertised to another BGP speaker unless that same prefix resides in the IBGP speaker’s local IGP table.

Basically this rule was set to stop blackholing routes. This rule is well defined in RFC 1745 and it possesses another requirement, and that’s when OSPF is the IGP used within the AS. This rule does not apply if the IGP is NOT OSPF.

This RFC states that if OSPF is used as the IGP in the AS, the router ids of OSPF and BGP on the border router, which is the router that performs the redistribution of BGP into OSPF must be the same.

to wit:

R2#sh run | b router
router ospf 1
 router-id 0.0.0.2
 redistribute bgp 234 subnets
 network 10.1.23.0 0.0.0.255 area 0
!
router bgp 234
 synchronization
 bgp router-id 2.2.2.2
 bgp log-neighbor-changes
 neighbor 10.1.12.1 remote-as 100
 neighbor 10.1.23.3 remote-as 234
 neighbor 10.1.23.3 next-hop-self
 neighbor 10.1.34.4 remote-as 234
 neighbor 10.1.34.4 next-hop-self

not so fast with the router id's...

first:

R3#sh ip bgp | b Net
     Network          Next Hop            Metric LocPrf Weight Path
 * i 1.0.0.0          10.1.23.2                0    100      0 100 i

good... now match the id's and clear bgp and ospf on r2...

R2#sh run | b router
router ospf 1
 router-id 2.2.2.2
 redistribute bgp 234 subnets
 network 10.1.23.0 0.0.0.255 area 0
!
router bgp 234
 synchronization
 bgp router-id 2.2.2.2

and this is what we accomplished... a rib failure...

R3#sh ip bgp | b Net
     Network          Next Hop            Metric LocPrf Weight Path
 r>i 1.0.0.0          10.1.23.2                0    100      0 100 i

and it's what we wanted...

R3#sh ip bgp rib-fa
  Network            Next Hop                      RIB-failure   RIB-NH Matches
1.0.0.0            10.1.23.2           Higher admin distance              n/a

although a route now exists in r5 to 1.0.0.0 there is no way back...

R5#sh ip route bgp | b Gate
Gateway of last resort is not set

B     1.0.0.0/8 [20/0] via 10.1.45.4, 08:33:40

r1 is still not in the game...

R1#sh ip route ospf
R1#

R2

router bgp 234
  neighbor 10.1.12.1 default-originate

and R4

R4(config)#router ospf 1
R4(config-router)#netw 10.1.45.4 0.0.0.255 area 0

solves the dilemma...

R1#sh ip route | b Gate
Gateway of last resort is 10.1.12.2 to network 0.0.0.0

B*    0.0.0.0/0 [20/0] via 10.1.12.2, 00:04:19

R5#ping 1.1.1.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 1.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 48/66/76 ms

narbik sync...

narbik is on the sync...

it's like the guy read my mind... i have never been satisfied with anyone's explanation of this shit...

whaddya mean you haven't downloaded it yet... hulk smash...

http://micronics.nl/BGP-Syn.pdf http://micronics.nl/BGP-Syn.pdf

tell me you love my ellipses... go ahead... who's your pal, who's your buddy...

up to the bgp verifications, and task 4...

R2#sh ip bgp summ | b Neighbor
Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.1.12.1       4          100      27      26        2    0    0 00:20:34        1
10.1.23.3       4          234      22      23        2    0    0 00:16:25        0
10.1.34.4       4          234      20      22        2    0    0 00:15:06        0

R3#sh ip bgp summ | b Nei
Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.1.23.2       4          234      23      23        1    0    0 00:17:13        1
10.1.34.4       4          234      19      18        1    0    0 00:15:31        0

R3#sh ip bgp | b Netw   
     Network          Next Hop            Metric LocPrf Weight Path
 * i 1.0.0.0          10.1.23.2                0    100      0 100 i

R4#sh ip bgp summ | b Nei
Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.1.23.2       4          234      24      22        1    0    0 00:16:36        1
10.1.34.3       4          234      19      20        1    0    0 00:16:13        0

include r4 and r5...

just follow the bouncing narbik...

R4#sh ip bgp summ | b Neigh
Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.1.23.2       4          234      31      29        1    0    0 00:23:06        1
10.1.34.3       4          234      26      27        1    0    0 00:22:44        0
10.1.45.5       4          500       0       0        1    0    0 never    Idle

R5#sh ip bgp summ | be Nei
Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
10.1.45.4       4          234       0       0        1    0    0 never    Idle

task 5 redist bgp on r2...

R2(config)#router ospf 1
R2(config-router)#redist bgp 234 subn
R2(config-router)#end

verify on r3...

R3#sh ip route ospf | b Gate
Gateway of last resort is not set

O E2  1.0.0.0/8 [110/1] via 10.1.23.2, 00:02:48, FastEthernet0/1
 
R3#sh ip bgp | b Net
     Network          Next Hop            Metric LocPrf Weight Path
 * i 1.0.0.0          10.1.23.2                0    100      0 100 i
R3#

just like new york...

R4#sh ip bgp | b Net
     Network          Next Hop            Metric LocPrf Weight Path
 * i 1.0.0.0          10.1.23.2                0    100      0 100 i
R4#ping 10.1.23.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.23.2, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 20/37/56 ms

this is the upshot...  reachability but no best route...

R4#sh ip bgp 1.0.0.0
BGP routing table entry for 1.0.0.0/8, version 0
Paths: (1 available, no best path)
  Not advertised to any peer
  Refresh Epoch 2
  100
    10.1.23.2 (metric 2) from 10.1.23.2 (2.2.2.2)
      Origin IGP, metric 0, localpref 100, valid, internal, not synchronized
      rx pathid: 0, tx pathid: 0

reason number 2013...

...that you should be digging into the cisco learning network... besides the fact i've posted many articles and downloadables there under my profile...

narbik on bgp synchronization, from the link below:

a downloadable pdf from the man, the myth...


http://micronics.nl/BGP-Syn.pdf http://micronics.nl/BGP-Syn.pdf

you can set up an account and receive automatic email notifications from the groups you belong to, on topics that interest you, because we live in the age of information transfer and shit...

this has been a public service announcement...

a mind is a terrible thing...

narbik...

another good reason to get your ass on cln...

• arteq

  977 posts since
  Sep 11, 2011

  18. Nov 26, 2012 2:31 AM (in response to Narbik)

  Re: CCIE R&S Experenice

  sorry to trouble you, but keith had me wondering; if i get the 4.0 bundle (lock lizard) then i can attend your bootcamp less the total cost of the bundle... your site is not clear on this... and is there an expiration on that? my point is i'd want a few months with the workbooks first... thanks for your time...

  • Edit
  • Delete
  • Reply
• 

  Narbik

  88 posts since
  Jun 15, 2011

  19. Nov 26, 2012 3:05 AM (in response to Keith)

  Re: CCIE R&S Experenice

  Arteq,
  

  
  

  If you purchase the bundle, that amount will be subtracted from the list price, let's say you are going to signup for the End-to-End boot camp, the price of this boot camp is $4500 for 12 days minus what you spent on the bundle.
  

  
  

  Narbik Kocharians

  CCSI#30832, CCIE# 12410 (R&S, SP, Security)

  www.MicronicsTraining.com

  Sr. Technical Instructor

  A Cisco Learning Partner

  • Report Abuse
  • Reply
• 

  arteq

  977 posts since
  Sep 11, 2011

  20. Nov 26, 2012 3:11 AM (in response to Narbik)

  Re: CCIE R&S Experenice

  thank you very much.... i will also inform my viewers of this on my site...
  

  
  

  http://insearchofthecert.blogspot.com

syslog and snmp...

last week i linked you to narbik's 2007 soup to nuts... for those of you who didn't immediately download it, put yourselves in network oblivion and go to bed without any bpdu's...

here it is again, lame one's...

http://insearchofthecert.blogspot.com/2012/03/old-school-tasty-treat.html

there is a bunch of stuff in there about configuring snmp traps...  here is the thing, and the gns3 guys can probably do this too, download something like kiwi's syslog server (it's free), slap it on a pc in your network that your lan devices can get to, turn on snmp on the lan devices and you can practice network management along with narbik's soup to nuts...

this is good stuff:

mls_1(config)#snmp-server host 10.1.1.100 public config tty ospf
mls_1(config)#snmp-server enable traps config
mls_1(config)#snmp-server enable traps ospf

traps are enabled by default for tty; note how you enable the pc's ip address and community string, and the individual traps for config changes and ospf events...

make sure you decide which items you want to trap or by default it will send everything; don't do that...

i'd like to hear some comments from those with gear, and the gns3 heads out there who make this happen...