Download - EIGRP routing protocol
![Page 1: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/1.jpg)
EIGRP routing protocol
Omer ben-shalom024200164
Omer Ben-Shalom:
Must show how EIGRP is dealing with count to infinity problem
Omer Ben-Shalom:
Must show how EIGRP is dealing with count to infinity problem
![Page 2: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/2.jpg)
Distance vector VS link state
Distance - shares all routes with neighbor routers and advertises many routes on one link change
Link state - shares only their own links but with all the routers in the AS/Area
Link state need not calculate before update so convergence is faster
![Page 3: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/3.jpg)
Distance vector problems Uses periodic full route update
Routing loops Accept any neighbor with lower metric Could have learned this from you or
someone you announced to Could fool each other endlessly (Count to
infinity), therefore network diameter is limited
Some are classfull
![Page 4: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/4.jpg)
Attempted solutions Split Horizon / Poison reverse
Do not advertise routes the way received (or) Set distance to on update Problematic in Non broadcast media
Hold down timers Hold update to routes with enlarged matrixes
Both cause large delay in convergence
![Page 5: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/5.jpg)
Link state protocols problems
Each node must know topology of the whole net, on LSA loses can become a problem
Complex to calculate: High memory requirements High CPU use if frequent changes
Harder to configure and troubleshoot
![Page 6: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/6.jpg)
The EIGRP Challenge Simple to implement like distance vector
Quick to converge like link state (By doing distributed calculations)
Use low bandwidth and low memory/CPU
Loop free
Classless
![Page 7: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/7.jpg)
Main features (1) Reliable transport
Reliable multicast (proprietary), if no response go to unicast (up to 16)
Use Sequence numbers (send/receive)
Link discovery - Hello protocol with hold time 3 X hello time (5/60 sec)
![Page 8: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/8.jpg)
Main features (2) Diffusing distributed algorithm (DUAL)
Modules to integrate with network layer protocols (IP, AppleTalk, IPX)
All updates are non-periodic, partial and bounded
![Page 9: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/9.jpg)
‘DUAL’ - diffusing algorithm.
Mark your cost to a route ,the next hop (successor) and the lowest cost (Feasible Distance)
Keep any neighbor with lower distance as possible replacement (Feasible Successor)
Reassess successors on any update or change
![Page 10: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/10.jpg)
‘DUAL’ (2) If successor still best - do nothing
(update neighbors)
If replacement exist in table the can be no loop so switch to it immediately and update
If no replacement change state to active and query all neighbors
![Page 11: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/11.jpg)
‘Dual’ (3) Every neighbor will start own
calculation based on data in query
Any neighbor not answering in timeout makes route ‘stuck in active mode’, neighbor removed from table and response assumed INF
After all ‘reply’ recalculate
![Page 12: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/12.jpg)
a
b
c
d
e
(0)
(1)
(2) (3)
(2)
Example 1 - Feasible successor
(All metrics are 1 hop)
![Page 13: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/13.jpg)
a
b
c
d
e
(0)
(1)
(2) (3)
(2)
![Page 14: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/14.jpg)
a
b
c
d
e
Q Q
()
(0)
(1)
(2) (3)
![Page 15: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/15.jpg)
a
b
c
d
e
R R
()
(0)
(1)
(2) (3)
32
![Page 16: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/16.jpg)
a
b
c
d
e
U U
(3)
(0)
(1)
(2) (3)
![Page 17: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/17.jpg)
a
b
c
d
e
(0)
(1)
(3)
Example 2 - No feasible successor
(Not all metrics are 1 hop)
(2)
(3)
![Page 18: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/18.jpg)
a
b
c
d
e
Q Q
()
(0)
(1)
(3) (3)
![Page 19: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/19.jpg)
a
b
c
d
e
(0)
(1)
(3)
R Q
Q
()
()
3
![Page 20: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/20.jpg)
a
b
c
d
e
(0)
(1)
(3)
R
R
()
()3
![Page 21: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/21.jpg)
a
b
c
d
e
(0)
(1)
(3)
R
U
()
(4)
4
4
![Page 22: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/22.jpg)
a
b
c
d
e
(0)
(1)
(3)
U U
(4)
(4)
44
![Page 23: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/23.jpg)
Main advantages to DUAL Simple
Converges as fast as link state
Recovery from loss involves no traffic if viable successor
No routing loops are possible Prevents problems Does not restrict network diameter
![Page 24: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/24.jpg)
Other interesting EIGRP points
Uses a sophisticated matrix of bandwidth, delay, load and reliability
Classless routing - carries the subnet mask
Allows CIDR (VLSM and route aggregation)
Can be authenticated by MD5
![Page 25: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/25.jpg)
Some last notes on EIGRP Proprietary to Cisco
On new neighbor discovery - form initial adjacency and pass whole route table
![Page 26: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/26.jpg)
Questions ?
![Page 27: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/27.jpg)
Extra data for questions EIGRP data structures:
link state table of neighbors list of neighbor route costs for all
neighbors EIGRP sequencing Active (waiting for reply) and passive
states explained Init with passive / 0 to self INF to all Drop passive neig with INF cost
![Page 28: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/28.jpg)
More data Router in active does not issue
updates or update structures until passive for that route
Answer either ‘no path’ or feasible successor for neighbor, only when all arrive change
The 4 active states ???
![Page 29: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/29.jpg)
Link state advantages Send only link changes not the resulting
route changes (smaller updates)
Propagates update before recalculation - faster convergence times.
Not prone to routing loops under normal circumstances
![Page 30: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/30.jpg)
Routing loops in distance vec.
An error or fail increases matrix for router
Paths to routers who are in loop (learned from himself for example) look better then ‘real’ paths
Stabilizes when all network learns of failure (potentially very lengthy)
![Page 31: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/31.jpg)
EIGRP packet types All under protocol number 88 Hello (5 sec multicast / 60 sec
unicast) ACK Update Query / Reply Request - not implemented
![Page 32: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/32.jpg)
EIGRP HEADER
Version Opcode Checksum
Flags
Sequence
Ack
AS number
TLVs
![Page 33: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/33.jpg)
IP Internal TLV
Type = 0x0102 Length
Next Hop
Bandwidth
MTU Hop CountReliability Load Reserved
DestinationPrefix len
Delay
Reserved External ID Flags
![Page 34: EIGRP routing protocol](https://reader036.vdocuments.us/reader036/viewer/2022062517/56814e32550346895dbb98f4/html5/thumbnails/34.jpg)
IP External TLV
Type LengthNext Hop
Bandwidth
MTU Hop CountReliability Load Reserved
DestinationPrefix len
Originating router
Originating AS
Arbitrary tag
Delay
External protocol metric
Reserved External ID Flags