Lets assume that three routers in the same network but at three different sites ( memphis.edu, arizona.edu, and colostate.edu) are connected to each other to construct the following topology:
-------------------------------------
| /ndn/edu/memphis/%C1.Router/router1 |
-------------------------------------
/ 11 12\
/ \
route-cost = 25 / \ route-cost = 30
/ \
17 / \ 13
------------------------------------- 7 10 --------------------------------------
|/ndn/edu/arizona/%C1.Router/router3|-------------------|/ndn/edu/colostate/%C1.Router/router2|
------------------------------------- route-cost = 28 --------------------------------------
Figure: Network Topology
The number represents the connecting face id. For example, /ndn/edu/memphis/%C1.Router/router1 is connected to /ndn/edu/arizona/%C1.Router/router3 via face 11 and the route cost is 25. To reach /ndn/edu/colostate/%C1.Router/router2 via face 12, the route cost is 30.
We will walk through setting up the faces and creating the configuration file for /ndn/edu/memphis/%C1.Router/router1.
Type the following in the terminal:
"nfd-status -f"
if you see ERROR: error while connecting to the forwarder (No such file or directory) message that means nfd is not running. Follow the instructions in Getting started with NFD to run nfd.
Lets assume that /ndn/edu/arizona/%C1.Router/router3 has hostname router3.arizona.edu and /ndn/edu/colostate/%C1.Router/router2 has ip address 79.123.10.145, and that all routers in the network had agreed to sync data in name prefix /ndn/nlsr/sync. /ndn/edu/memphis/%C1.Router/router1 will consider face uri udp4://router3.arizona.edu for router /ndn/edu/arizona/%C1.Router/router3 and face uri udp4://79.123.10.145 for router /ndn/edu/colostate/%C1.Router/router2.
Now, lets assume that /ndn/memphis.edu/router1 wants to advertise three name prefixes that can be reached through it ( /ndn/memphis/sports/basketball/grizzlies, /ndn/memphis/entertainment/blues, /ndn/news/memphis/politics/lutherking). Now, the configuration file with minimum configuration commands will have the following commands
; nlsr.conf starts here
; the general section contains all the general settings for router
general
{
; mandatory configuration command section network, site and router
network /ndn/ ; name of the network the router belongs to in ndn URI format
site /edu/memphis/ ; name of the site the router belongs to in ndn URI format
router /%C1.Router/router1 ; name of the network the router belongs to in ndn URI format
; lsa-refresh-time is the time in seconds, after which router will refresh its LSAs
lsa-refresh-time 1800 ; default value 1800. Valid values 240-7200
; log-level is to set the levels of log for NLSR
log-level INFO ; default value INFO, valid value DEBUG, INFO
log-dir /var/log/nlsr/
seq-dir /var/lib/nlsr/
}
; the neighbors section contains the configuration for router's neighbors and hello's behavior
neighbors
{
; in case hello interest timed out, router will try 'hello-retries' times at 'hello-time-out'
; seconds interval before giving up for any neighbors (deciding link is down)
hello-retries 3 ; interest retries number in integer. Default value 3
; valid values 1-10
hello-timeout 1 ; interest time out value in integer. Default value 1
; Valid values 1-15
hello-interval 60 ; interest sending interval in seconds. Default value 60
; valid values 30-90
; neighbor command is used to configure router's neighbor. Each neighbor will need
; one block of neighbor command
neighbor
{
name /ndn/edu/arizona/%C1.Router/router3 ; name prefix of the neighbor router consists
; of network, site-name and router-name
face-uri udp4://router3.arizona.edu ; face uri of the face connected to the neighbor
link-cost 25 ; cost of the connecting link to neighbor
}
neighbor
{
name /ndn/edu/colostate/%C1.Router/router2 ; name prefix of the neighbor router consists
; of network, site-name and router-name
face-uri udp4://79.123.10.145 ; face uri of the face connected to the neighbor
link-cost 30 ; cost of the connecting link to neighbor
}
}
; the hyperbolic section contains the configuration settings of enabling a router to calculate
; routing table using [hyperbolic routing table calculation](http://arxiv.org/abs/0805.1266) method
hyperbolic
{
; commands in this section follows a strict order
; the switch is used to set hyperbolic routing calculation in NLSR
state off ; default value 'off', set value 'on' to enable hyperbolic routing table
; calculation which turns link state routing 'off'. set value to 'dry-run"
; to test hyperbolic routing and compare with link state routing.
radius 123.456 ; radius of the router in hyperbolic coordinate system
angle 1.45 ; angle of the router in hyperbolic coordinate system
}
; the fib section is used to configure fib entry's type to ndn FIB updated by NLSR
fib
{
; the max-faces-per-prefix is used to limit the number of faces for each name prefixes
; by NLSR in ndn FIB
max-faces-per-prefix 3 ; default value 0. Valid value 0-60. By default (value 0) NLSR adds
; all available faces for each reachable name prefixes in NDN FIB
}
; the advertising section contains the configuration settings of the name prefixes
; hosted by this router
advertising
{
; the ndnname is used to advertised name from the router. To advertise each name prefix
; configure one block of ndnname configuration command for every name prefix.
prefix /ndn/memphis/sports/basketball/grizzlies
prefix /ndn/memphis/entertainment/blues
prefix /ndn/news/memphis/politics/lutherking
}
; security configuration is discussed
;[NLSR's security configuration](https://github.com/named-data/NLSR/blob/master/docs/SECURITY.md)
; which will be also part of this configuration file here
;
; nlsr.conf end here
Assuming the configuration file is saved as nlsr.conf. Type the following to run nlsr
$ nlsr -f nlsr.conf
NLSR will look for nlsr.conf in the current directory. If nlsr.conf is not in the corrent directory, please provide the absolute path with the file name as the value. If nlsr.conf resides in /home/ndnuser/configuration directory, type "nlsr -f /home/ndnuser/configuration/nlsr.conf" to run nlsr.
The same process needs to be followed for router /ndn/arizona.edu/router3 and /ndn/colostate.edu/router2 to run NLSR on these routers.
Assuming that all three routers are configured correctly and converged, nfd-status in /ndn/edu/colostate/%C1.Router/router2 will have the following entries for the name advertised by /ndn/edu/memphis/%C1.Router/router1. This output can be seen by typing nfd-status -b in terminal
FIB:
/ndn/memphis/sports/basketball/grizzlies nexthops={faceid=17 (cost=25), faceid=7 (cost=58)}
/ndn/memphis/entertainment/blues nexthops={faceid=17 (cost=25), faceid=7 (cost=58)}
/ndn/news/memphis/politics/lutherking nexthops={faceid=17 (cost=25), faceid=7 (cost=58)}
Please refer to the network figure for face id. Numbers at the end of each link correspond to face ids.