Bandwidth Management Features
General
HotPools
Time of Day Routing
Any combination of fixed or dynamic bandwidth per Route (0K to 512K).
WarpTwo routers may operate in 'stand-alone' mode in which case they will have a single ISDN BRI (with 2 B Channels).
The router may be configured to support two concurrent connections to two independent destinations each using a single B Channel (64K bits per second) or a single connection to one destination using either 1 B channel (64K bits per second) or 2 B Channels (128K bits per second).
WarpTwo may also be configured to operate in 'HotPools' mode. HotPools is a sophisticated distributed resource management protocol. In this case multiple routers (the Pool) will act together as a single entity to create a total bandwidth equal to the sum of all the available channels (i.e. 2 routers will have 4 channels or 256K bits per second, 4 routers will have 8 channels or 512K bits per second).
The 'Physical route' properties (part of the User Profile) define how many links
are to be used. A Route Master (the router containing the User Profile and Authentication information for the
'Physical Route') controls the allocation of available bandwidth from the Pool. All other routers act as Route Slaves.
Multiple concurrent “Physical’ routes supported.
'HotPools' also allows the Pool of routers to use all the available channels in the
Pool to service as many Physical Routes as are defined by all the routers in the Pool. Each router may act as both a Route Master (if it contains the User Profile and Authentication information) and a Route Slave for any other router if requested by
a Route Master. Thus data arriving for a connection which is not currently open
will cause the Route Master for that Physical Route' to obtain either a local
channel (if it has one free - it may also be acting as a Slave for another Route
Master) or request another router which has a free channel to act as a slave. If
this request is accepted the Master supplies all the connection information
(excluding Authentication information which NEVER travels on the network) and
the Slave creates and negotiates the LCP connection. Authentication is then
carried out by the Route Master and finally the Master may need to initiate an
IPCP NCP on the link.
User configurable Route Idle Timer (5 to 32,000 seconds).
The Idle Timer property is defined on a 'per Physical Route' basis and may lie in the range 5 to 32,000 seconds. The Idle Timer determines how often capacity checks are made (and together with the Usage Window property) when bandwidth (links)
is added or removed. Thus, a Physical Route whose Idle Timer property is set to 5
(seconds) may add or remove a link every 5 seconds. In order to minimize the time an idle link is open the router uses an Idle Window concept such that as soon as there is a contiguous period of idle seconds equal to the
Idle Timer property the link will be closed. In practice this can reduce link open time by as much as the Idle Time - 1 second. To illustrate, assume an
Idle Timer property of 30 seconds (a normal setting). further assume data stops transmitting 1 second after the last
Idle Timer period expired. At the next capacity check the Idle Timer would not be satisfied
(data was transmitted during the period) and the link would stay open. If the Idle Window is not applied the Link would stay open until the next Idle Timer check i.e. a total of 59 seconds without any transmission before closing the link. When the Idle Window is applied the link closes after 30 seconds of contiguous idles (1 second after the first Idle Timer check and a full 29 seconds before the next one). Over a period of time
these small numbers can become significant. Without this feature you could (pathologically perhaps) be paying 49% of the time for 'nothing' in our example. This is yet another example of the ZyTrax
optimization of resource utilization. As with all parameters this is controlled
via the SNMP MIB and can be changed in real-time without service interruption.
Housekeeping traffic is excludes from all Idle Timer calculations and will
therefore NOT keep a link open. Housekeeping traffic (traffic used to maintain
the link but does not contain user data) is defines as - all protocol traffic (inlcuding
LCP echo requests), Multicast overheads e.g. IGMP membership requests.
User configurable Usage Window used to add or remove dynamic capacity (5 - 95%).
The Usage Window property is defined on a 'per Physical Route' basis
and defines the percentage of available capacity that must be used before adding
or removing bandwidth. The Usage Window is used during capacity check periods
(on every expiration of the Idle Timer). A low Usage Window value 5 - 20% will
give a fast add and slow subtract of capacity, a high value will give a slower
rise and faster fall in capacity. The nature/characteristics of the traffic that
is most frequently used will determine the operational value of this parameter.
As with all parameters this is controlled via the SNMP MIB and can be changed in
real-time without service interruption.
User configurable number of 'Bumpable' Links per Route.
Each 'Physical Route' may
optionally have defined a number of 'Bumpable' links. A 'Bumpable link' is
one that may be removed from the connection as long as the number of
channels remaining is not below the number of Fixed links. 'Bumpable'
links may be used for making of voice calls in models with analog
connections or when multiple routes are being supported. Assume that a
'Physical Route' is defined as having a Maximum of 2 links with a fixed
capacity of 1 link. Suppose further that a second 'Physical Route' is
similarly configured. This allows both routes to operate and dynamically
take advantage of the maximum available performance (the alternative is to
statically define 1 link per route). However if one route is using
both channels and the other 'Physical Route' becomes active then the
'Bumpable' Link property is used to remove 1 link from the 'Physical
route' currently using 2 links. As with all parameters this is controlled
via the SNMP MIB and can be changed in real-time without service
interruption.
All bandwidth properties may be configured by Time of Day and/or Day of Week.
Bandwidth needs may vary
radically with time. Daytime browsing needs may be higher than overnight
FTP loads. The user may not require any bandwidth after 6PM. Web and FTP
site utilization may increase dramatically during another time zone's
daytime usage. The user may define the bandwidth properties using three
Time of Day slots per Physical Route based on the day of the week or time
of day (or both). As with all parameters this is controlled via the SNMP
MIB and can be changed in real-time without service interruption.
Multiple Routers combine to form a single Route (0K to 512K) of bandwidth.
The 'Physical Route'
properties define how each 'end' of a connection sees the connection.
WarpTwo has a simple arbitration rule. If an incoming call arrives the
other end (the initiator) knows what it is doing so it controls the Link
(the receiving router will only remove this link based on the 'Bumpable'
links parameter). This simple concept allows significant efficiencies of
usage and removes the need for time consuming and inflexible bandwidth
negotiation schemes. It further allows control to reside on one end of the
link or for both ends to co-operate.
Multiple Routers (A Pool) support up to 80 Routes on a dynamic basis.
The 'Physical Route'
properties define how each 'end' of a connection sees the connection.
WarpTwo has a simple arbitration rule. If an incoming call arrives the
other end (the initiator) knows what it is doing so it controls the Link
(the receiving router will only remove this link based on the 'Bumpable'
links parameter). This simple concept allows significant efficiencies of
usage and removes the need for time consuming and inflexible bandwidth
negotiation schemes. It further allows control to reside on one end of the
link or for both ends to co-operate.
HotPools allows either or both ends to initiate additional bandwidth
demands.
The 'Physical Route' properties
define how each 'end' of a connection sees the connection. WarpTwo has a simple
arbitration rule. If an incoming call arrives the other end (the initiator)
knows what it is doing so it controls the Link (the receiving router will only
remove this link based on the 'Bumpable' links parameter). This simple concept
allows significant efficiencies of usage and removes the need for time consuming
and inflexible bandwidth negotiation schemes. It further allows control to
reside on one end of the link or for both ends to co-operate.
Both ends of a connection may be configured to have different Route properties.
This is particularly useful
where you want to control who adds capacity but you want both 'ends' to be
able to create a minimal link. In, say, a PVA connection you may want the service provider to be able to make a single connection (the providers Max. Links property would be 1) but you may use up to 4 Links (your router's Max. Links property would be set to
4).
Single configuration parameter
controls the HotPool feature.
The user can establish any
number of HotPools e.g. a Pool of 128K connections, a Pool of 384K
connections. Each Router is configured to join a specific Pool (an
arbitrary Pool number) at which point it exchanges configuration
information with all other routers in that Pool and thus the Pools
topology and resources are know to all other members of the Pool. To
remove the Router from the Pool change its Pool Number to 0 (the Dead
Pool) or to the New Pool number. As with all parameters this is controlled
via the SNMP MIB and can be changed in real-time without service
interruption.
Route properties may be configured by Time of Day or Day of the Week.
The user may define the
bandwidth properties using three Time of Day slots per 'Physical Route'
based on the day of the week, time of day or the type of day (week day,
week-end). Thus it is possible to define a usage pattern which uses 2
Fixed links from 7AM to 6PM Monday to Friday and 0 links at any other
time, or Dial access on Sunday and fixed access at all other times or a
Maximum of 2 links, 1 fixed from 5AM to 12PM then the maximum capacity
becomes 6 links with 2 fixed, except for Saturday when 6 links will be
fixed from 8AM to 12PM. As with all parameters this is controlled via the
SNMP MIB and can be changed in real-time without service interruption.
Routes may have up to 3 Time of Day (ToD) slots.
The user may define the
bandwidth properties using three Time of Day slots per 'Physical Route'
each slot runs until completion at which time it is superceded by the next
slot that meets the criteria e.g. it is 5PM Sunday. Using 3 ToD slots
provides endless permutations to reduce costs and/or add dynamic capacity
to service need. As with all parameters this is controlled via the SNMP
MIB and can be changed in real-time without service interruption.
Maximum Links can be configured as 0 to enable complete Route shut-down.
Setting a Time of Day slot
with a Maximum Links property of 0 causes the system to shut down
completely at the end of the first Idle Timer period in the new ToD slot.
This feature allows users to safely leave computers switched on and not
worry about 'dirty web sites' continually refreshing displays (consuming
time and money). As with all
parameters this is controlled via the SNMP MIB and can be changed in
real-time without service interruption.
Incoming calls are
accepted in a 0 Link mode to allow essential functions.
If incoming calls are allowed they will be accepted in 0
Link mode (i.e. when the Maximum Link property is 0). This feature is
designed to allow system administrators to carry out maintenance,
configuration or other tasks when the system would otherwise not be
available.
Temporary ‘extensions’ are allowed in
0 Link mode.
The use can 'temporarily' open a 0 Link connection. The link is
opened for the time period specified and them reverts to its original schedule.
This features was designed to prevent users accidentally leaving links open
over, say, a week-end and forces the user to define a change 'duration' period.
