Thursday, December 23, 2010

OSPF over Frame-relay

I just wanted to drop a line that has helped me tremendously the last couple of months. Its hard to remember sometimes what goes into an ospf config when using frame as your medium. Remember this:

"Non-broadcast Needs Neighbors"

If the network type is the default of non-broadcast, or point-to-multipoint non-broadcast you will have to include neighbor statements in your ospf configs. HTH's!

-Jason

Monday, December 13, 2010

Routing Protocols Comparison Poster

I kind of threw this together for my written. It is a pdf in its natural state, if you want a copy of the pdf email me at willroute4food at gmail dot com. Its just a good quick side-by-side of some of the major routing protocols. If you find an error, or something I should add please let me know in the comments (I do realize some of the numbers were thrown off in the conversion. The data does appear to be in the appropriate containers though). Thanks.




RIP (version 2)
OSPF
EIGRP
BGP
IP Protocol number, (TCP)
n/a
IP 89
IP 88
TCP 179
Hello Address
224.0.0.9 (can be set to broadcast at the interface level via ip rip v2-broadcast)
224.0.0.5 –AllOSPFRtrs
224.0.0.6 –DR/BDR
224.0.0.10
Unicast hello to configured “neighbor”
Administrative Distance(s)
120
110
Internal – 90
External – 170
Summary -- 5
EBGP – 20
IBGP – 200

Metric (calculation) / Limits
Hop Count/ Limit is 15 hops, 16 is inaccessible
Cost = Autocostrefbw/interface bandwidth
*Default is 100Mb for Autocostrefbw*
Cost  = 256(BW + Delay)
*formula with default K values)
The maximum number of hops that EIGRP will accept is 100 by default, although the maximum can be configured to 220 with metric maximum hops.
IBGP – 0
Redistributed routes metric = IGP metric
Timers
Update-30
Invalid-180
Holdown-180
Flush-240
Hello – 10/30
Dead – 40/120
Hello – 5/60
Hold – 15/180
Keepalive – 60
Holdtime -- 180
Adjacency (neighbor) Requirements
Neighbor must be on a subnet off of primary interface included in “network” statement
1.       Pass authentication checks
2.       Same primary subnet w/mask
3.       Same OSPF area
4.       Same Area type (flags)
5.       NOT duplicate RIDS
6.       Hello/Dead timers must match
7.       Unless P2P (one must be DR/BDR)
1.       Pass authentication checks
2.       Must have same AS number
3.       Must believe that source IP of neighbor in hello is in that routers primary subnet (no secondary’s)
4.       K values must match
1.       Source IP in connection request must match something in the local routers “neighbor” statements.
2.       Routers ASN must match its corresponding ASN in “neighbor stmt
3.       RIDS must be different
4.       Must pass MD5 authentication
Passive Interface (yes,no) /Affects
Yes/Shuts off the sending of updates on the passive interface.  Will still listen to updates and will update routing table accordingly
Yes/Stops sending hello’s /updates out of that interface.  Note though, if included in the network statement the network on that interface will still be advertised to peers.
Yes/suppresses both incoming AND outgoing hellos/updates.  Note that it will not allow neighbors to form. 
n/a
Auto-summarization
Enabled by default
n/a
Enabled by default (wont summarize route that it does not “own”)
Disabled by default after 12.3 mainline
Summary Address
(conf-if) ip summary-address rip ip-address ip-network-mask
default-information originate [route-map map-name]
ABR- area x range ip-address mask {advertise | no-advertise} cost cost

(router) summary-address ip-address mask
(conf-if) ip summary-address eigrp [as] ip-address mask
aggregate-address address mask [as-set] [summary-only] [suppress-map map-name] [advertise-map map-name] [attribute-map map-name]
neighbor x.x.x.x default-originate
network 0.0.0.0 (OR STATIC ROUTE/REDISTRIBUTE)
Filtering Method(s)
distribute-list {access-list-number | prefix prefix-list-name [gateway prefix-list-name]} in [interface-type interface-number]
Inbound – distribute-list {prefix | route-map} in
In/out – area (number) filter-list prefix (name) {in | out}
Distribute-list {access-list num/name}  {prefix list-name}  {in | out}  {int type/num}
Prefix-lists, route-maps, filter-lists, etc….

Authentication
Clear text or MD5
16 character limit

Key chain RIP
Key 1
Key-string cisco

Int fa0/0
Ip rip authentication key-chain RIP
Ip rip authentication mode md5
0 – none, 1 – clear text, 2 – MD5
Int fa0/0
Ip ospf authentication
Ip ospf authentication-key {key}

Int fa0/0
Ip ospf authentication message-digest
Ip ospf message-digest-key {number} md5 {key}

You can also declare the authentication type under the router OSPF process
MD5 only

Key chain EIGRP
Key 1
Key-string cisco

Int fa0/0
Ip authentication mode eigrp [as] md5
Ip authentication key-chain EIGRP [as] EIGRP
MD5 only

Neighbor x.x.x.x password [pass]
Offsets
Increases incoming or outgoing hop count on routing updates (CAN BE USED TO FILTER BY SETTING HOP COUNT > 15)
Access-list 1 permit 10.10.10.0 0.0.0.255

Router rip
Offset-list 1 out 5 serial0
//increases metric by 5 on that route//
n/a
access-list 1 permit 10.1.1.0 0.0.0.255
router eigrp 1
offset-list 1 out 3 FastEthernet0/0
n/a