home 
wiki
wiki
Spelling: NodeTypes
* Introduction [1]
* Logical view of different nodes: [2]
* Client Nodes [3]
* Dx Node [4]
* Cx Node [5]
* Bx Node [6]
* Ax Node [7]
* Variations [8]
* Bx Cx Hybrid [9]
* Re-trans [10]
* Hypothetical example [11]
* Node Examples [12]
* RGInnerNorth [13]
* Southern [14]
* Dandenong Foothills [15]
INTRODUCTION
While the wireless network in Melbourne is in it's infancy other
communities have very well developed infrastructure. In the US
community networks are not necessary providing an alternative network
to the ISP provided ones but are rather providing wireless access for
community members whereever they are.These networks are successful as
there is no bandwidth limits from the regular ISP's and every coffe
shop is able to hook up a DSL modem and an AP to become a node.
In the well developed "geek" centres (Bay Area, Seattle, Austin among
others) the local wireless orgs assist the setup of nodes to enlarge
the coverage of the network. That's not to say they don't build
backbone infrastructure as it is also high on their objectives but
citywide access for members seems to be the driving factor.
Here in AUS it's a little different as the lack of competition means
that most ISP's still gouge their customers and apply fairly draconian
conditions (about what you can hook up, sharing your bandwidth, etc.).
The Melbourne Wireless network is pretty fragmented at the moment.
There are pools of linked nodes but no city wide backbone yet. That
seems to be the primary goal for the group at the moment. Creating a
backbone is very dependant on individuals that want ot be part of it.
So what is a node and do you have one yet?
Seattle Wireless probably has the best classification of node types:
* Client Node
* Dx Node
* Cx Node
* Bx Node
* Ax Node (or Super Bx Node)
These node definitons really need to be applied a bit loosely as in
reality a node will start out as one type and morph into a different
type depending on the availability of other nodes to link to. Perhaps
the most common variation would be a hybrid Bx-Cx that would have
links to other nodes and support either Client Nodes or Cx Nodes on
the BSS interface.
Another common evolution would be a node that starts out running a
BSS interface and has a number of other nodes pointng their uplink
links to it. In this case the links may be sub-optimal but are likely
to suffice for the amount of traffic and usage of the connected nodes.
(Note that as the discrete areas of connectivity coalesce and the
network becomes used more that these types of "shared" connections
will become bottlnecks in the network).
LOGICAL VIEW OF DIFFERENT NODES:
CLIENT NODES
A Client Node is a node that connects to a Dx Node or Cx Node,
typically using BSS mode. It could be a PC, laptop or handheld device.
A Client Node could be fixed or mobile.
DX NODE
Dx Nodes is a node without any upstream connection, this is typically
the node you install at home when you want to get wireless in your
house. It allows your wireless devices to be part of your home LAN and
you may have internet access for your own personal use. In this
scenario you keep the node closed and may use some form of encryption
(weak though it may be).
+-----------------+ | | | | | +-----+ | | BSS |---/--- to Client
Nodes | +-----+ | | | | +-----------------+
CX NODE
Cx Node is a node with one upstream connection. A Cx Node connects to
a single Bx Node. The CxNode [16] accepts connections from Client
Nodes and routes thouse requests to it's upstream connection. At this
level routing is easy. The Cx Node is the on-ramp to the local
wireless network.
+-----------------+ | | | | | +------+ | | BSS | ---/--- to Client
Nodes | +------+ | | | +------+ | | IBSS | +++++++++ to upstream Bx
Node | +------+ | | | | +-----------------+
BX NODE
Bx Nodes support a pool of Cx Nodes and have two links to other Bx
Nodes provides DHCP to the client Cx Nodes and intellegent routing. So
a Bx Node has 3 radios, one for supporting the Cx Node pool and two
more for making redundant links to the rest of the backbone using two
other Bx Nodes.
+-----------------+ | | | | | +------+ | | BSS | ---/--- to Cx Nodes
| +------+ | | | +------+ | | IBSS | +++++++++ to peer Bx Node |
+------+ | | | +------+ | | IBSS | +++++++++ to peer Bx Node |
+------+ | | | | +-----------------+
AX NODE
Ax Nodes or Super Bx Nodes have more then 3 radios and tend not to
support a client cloud ( no Cx Nodes hanging of it). It provides
routing between it's multiple interfaces.
VARIATIONS
A number of variations of this classification exist. Perhaps the most
common are nodes that provide a hybrid functionality betwen a Cx Node
and a BX Node. This is common in a young network such as ours as it is
more important to get some links in place than to do it in a strictlu
herachical sense.
BX CX HYBRID
A node that could qualify as a BX Node is more of well linked Cx
Node. This node has the typical Cient Nodes but also has a link (or
two) to other Bx Nodes on the same interface. The ideal situation
would be for this node to have a dedicated raido(s) for the links to
the Bx Nodes but for the time being the conncetion is established
using the omni interface of the node.
RE-TRANS
A re-trans is a pair of radios that provide linkage between two nodes
that would not otherwise be able to connect. A retrans may be
desirable due to terrain and the lack of suitable nodes in the
location.
HYPOTHETICAL EXAMPLE
In this example a number of Bx Nodes are configured in the same
manner. They use Ch 6 in IBBS mode to communicate to one or more Cx
Nodes that in turn use Ch12 in BSS mode to commuicate with a number of
Client Nodes. This is kind of an ideal situation, each Bx Node has 3
radios with dedicated links. In reality many of our Nodes will be less
optimal.
| +-----+IBBS +------+ | BxN [17] |---/--- -->|Client| +-----+Ch 6 /
+------+ IBBS|Ch 1 / +-----+IBSS +-----+BSS / +------+ | BxN [18]
|---/--->| CxN [19] |---/--->|Client| +-----+Ch 6 +-----+Ch12 +------+
| | +------+ This client could roam between the IBBS|Ch 11 -->|Client|
the two CxN [20] if they used the same ESSID | / +------+ | /
+-----+IBSS +-----+BSS / +------+ | BxN [21] |---/--->| CxN [22]
|---/--->|Client| +-----+Ch 6 +-----+Ch 1 +------+ IBBS|Ch 1
+-----+IBBS +------+ | BxN [23] |---/--- -->|Client| +-----+ +------+
|
NODE EXAMPLES
Looking at the node finder we can see that there is not a lot of
linkage activity in our network yet. Some areas are well on the way to
creating isolated Bx Nodes that serve potential Cx Nodes but we don't
have much in the way of Bx Node linkage.
RGINNERNORTH
NodeBHH [24] is a great example of an almost-Bx Node. There are lots
of links sharing the same radio and some of these links are potential
Bx Nodes. This is an example of growing and changing as needed. If one
of the linked sites establishes a further link to another potential Bx
Node then BHH may drops it from the BSS connection and establshes a
dedicated link (or perhaps not!).
BSS|Ch 6 | +-----+BSS >| FUS |---/--- Bx----+Ch 3 +-----+BSS
+-----+BSS | BHH |---/--- >| FZJ |---/--- +-----+Ch 11 Cx----+Ch 3
+-----+BSS >| FMK |---/--- Cx----+Ch 8 +-----+? >| FNZ |---/---
Cx----+Ch ? +-----+ >| DCH | (ClientNode or Dx Node) +-----+ +-----+
>| HFL | (ClientNode?) +-----+
* NodeFZJ [25] is a Cx Node. It has a p2p link back to BHH and has an
omni for client connections.
* NodeFNZ [26] is another Cx Node with the backlink to NodeBHH [27]
* NodeDCH [28] looks like it has only one interface as either the
backlink to NodeBHH [29] (ClientNode). or acting as a Dx Node in omni
role.
* NodeHFL [30] looks like it has the backlink only, so is a Client
Node.
* NodeFMK [31] is a Cx Node with the uplink to NodeBHH [32].
* NodeFUS [33] is another Bx Node in waiting. It has 3 radios, on
connected p2p to BHH, another p2p (presumably waiting for someone to
connect it to - how about GPR?) and an omni for Cx Node or client
connections.
SOUTHERN
So whats going on here? NodeGMR [34] and NodeGES [35] are Bx Nodes
and AFH and FBD are on their way to being the same. Again the use of
BSS and linking into the omni of a neighboring node seems to be the
norm, the Bx Cx hybrid we saw in the other example.
+-----+ | HZN | +-----+ | | IBSS|Ch ? IBSS|Ch 2 | | +-----+BSS
+-----+BSS +-----+BSS +-----+BSS | GMR |---/--- >| GES |---/--- >| AFH
|---/--- >| FBD |---/--- Bx----+Ch 4 Bx----+Ch 1 Cx----+Ch 4 Cx----+Ch
1 | BSS|Ch ? | +-----+ >| GEZ | +-----+
DANDENONG FOOTHILLS
Classic Bx Node structure here.
BSS|Ch ? | +-----+BSS +-----+BSS +-----+BSS | AAF |---/--- >| GUR
|---/--- >| HKF |---/--- Cx----+Ch ? Bx----+Ch 8 Cx----+Ch 6 | |
+-----+ +-----+ | >| FGH | >| HUT | | +-----+ +-----+ | | +-----+
+-----+ | >| FUT | >| ICW | IBSS|Ch 6 +-----+ +-----+ | | +-----+
+-----+ | >| HCL | >| HNB | | +-----+ +-----+ | | +-----+ | >| GAZ | |
+-----+ | +-----+BSS +-----+BSS +-----+BSS +-----+ | FKR |---/--- >|
HKR |---/--- >| GWS |---/--- >| BFI | Bx----+Ch 1 Cx----+Ch 10
Bx----+Ch 11 +-----+ | | BSS|Ch ? +-----+ BSS|Ch 1 | >| HLR | |
+-----+ +-----+ >| HMF | +-----+ +-----+ >| FRJ | +-----+
Links:
------
[1] http://melbournewireless.org.au/#introduction
[2] http://melbournewireless.org.au/#logical_view_of_different_nodes_
[3] http://melbournewireless.org.au/#client_nodes
[4] http://melbournewireless.org.au/#dx_node
[5] http://melbournewireless.org.au/#cx_node
[6] http://melbournewireless.org.au/#bx_node
[7] http://melbournewireless.org.au/#ax_node
[8] http://melbournewireless.org.au/#variations
[9] http://melbournewireless.org.au/#bx_cx_hybrid
[10] http://melbournewireless.org.au/#re_trans
[11] http://melbournewireless.org.au/#hypothetical_example
[12] http://melbournewireless.org.au/#node_examples
[13] http://melbournewireless.org.au/#rginnernorth
[14] http://melbournewireless.org.au/#southern
[15] http://melbournewireless.org.au/#dandenong_foothills
[16] http://melbournewireless.org.au/?CxNode
[17] http://melbournewireless.org.au/?BxN
[18] http://melbournewireless.org.au/?BxN
[19] http://melbournewireless.org.au/?CxN
[20] http://melbournewireless.org.au/?CxN
[21] http://melbournewireless.org.au/?BxN
[22] http://melbournewireless.org.au/?CxN
[23] http://melbournewireless.org.au/?BxN
[24] http://melbournewireless.org.au/?NodeBHH
[25] http://melbournewireless.org.au/?NodeFZJ
[26] http://melbournewireless.org.au/?NodeFNZ
[27] http://melbournewireless.org.au/?NodeBHH
[28] http://melbournewireless.org.au/?NodeDCH
[29] http://melbournewireless.org.au/?NodeBHH
[30] http://melbournewireless.org.au/?NodeHFL
[31] http://melbournewireless.org.au/?NodeFMK
[32] http://melbournewireless.org.au/?NodeBHH
[33] http://melbournewireless.org.au/?NodeFUS
[34] http://melbournewireless.org.au/?NodeGMR
[35] http://melbournewireless.org.au/?NodeGES
[EditText] [Spelling] [Current] [Raw] [Code] [Diff] [Subscribe] [VersionHistory] [Revert] [Delete] [RecentChanges]