CushionTheBlow (구 BluemoonSoft)

Customer-premises equipment or customer-provided equipment (CPE) is any terminal and associated equipment and inside wiring located at a subscriber's premises and connected with a carrier's telecommunication channel(s) at the demarcation point ("demarc"). The demarc is a point established in a building or complex to separate customer equipment from telephone company equipment.

CPE generally refers to telephones, DSL modems or cable modems, or purchased set-top boxes for use with Communications Service Providers' services. Also included are key telephone systems and most private branch exchanges. Excluded from CPE are overvoltage protection equipment and pay telephones.

Cellular carriers may sometimes internally refer to cellular phones a customer has purchased without a subsidy or from a third party as Customer Provided Equipment.

It is also notable that the Fully qualified domain name of DSL and cable lines connected to a residence will often be prefixed with 'cpe'.

Reference:
http://en.wikipedia.org/wiki/Customer-premises_equipment

A key system or key telephone system is a multiline telephone system typically used in small office environments.

Key systems are noted for their expandability and having individual line selection buttons for each connected phone line, however some features of a private branch exchange such as dialable intercoms may also commonly be present.

Key systems can be built using three principal architectures:

Electromechanical shared-control
Electronic shared-control
Independent keysets

Reference:
http://en.wikipedia.org/wiki/Key_telephone_system

관련 뉴스들:
http://www.dt.co.kr/contents.htm?article_no=2007013002010151693001, 광가입자망 시장 AON 두각 (하나로ㆍKT 수도권 단지 구축, 수동형보다 경제성 좋아 선호)
http://www.zdnet.co.kr/news/network/etc/0,39031057,39141726,00.htm, 광가입자망 장비시장「AON 기술」급부상 (PON의 절반가격…기능은 100Mbps급 제공)
- 통방융합, 유무선 통합 등을 지원할 광가입자망(FTTH) 장비시장에 경제성을 앞세운 AON(능동형 광네트워크) 기술이 새롭게 급부상하고 있다.

The Link Aggregation Control Protocol (LACP) is a computer networking term and is part of IEEE specification 802.3ad that allows bundling several physical ports together to form a single logical channel. LACP allows a network switch to negotiate an automatic bundle by sending LACP packets to the peer. LACP is a protocol implementation in OSI layer 2 which controls through which physical links the traffic will be routed.

Advantages
- Increases bandwidth
- Failover when link status fails on a port.

Practical notes
Several links can be bundled into a single logical link, enabling:
- higher bandwidth connections
- enhanced bandwidth granularity
- load sharing
- fault tolerance protection

The user may aggregate ports into link-aggregation port groups. These groups are treated as individual logical ports. Each group is composed of ports with the same speed, set to full-duplex operation.

The group is represented by a logical Aggregator which offers a standard IEEE 802.3 MAC service interface. An Aggregator can therefore be considered to be a logical MAC, bound to one or more ports.

A single, individual MAC address is associated with each Aggregator.

LACP (802.3ad) for Gigabit Interfaces Feature Overview
The LACP (802.3ad) for Gigabit Interfaces feature bundles individual Gigabit Ethernet links into a single logical link that provides the aggregate bandwidth of up to 4 physical links. A Cisco 10000 series router supports a maximum of 4 Gigabit Ethernet bundled ports per port channel and a maximum of 64 Gigabit Ethernet port channels per chassis.

All LAN ports on a port channel must be the same speed and must all be configured as either Layer 2 or Layer 3 LAN ports. If a segment within a port channel fails, traffic previously carried over the failed link switches to the remaining segments within the port channel. Inbound broadcast and multicast packets on one segment in a port channel are blocked from returning on any other segment of the port channel.

References:
http://en.wikipedia.org/wiki/Link_Aggregation_Control_Protocol
http://www.cisco.com/en/US/docs/ios/12_2sb/feature/guide/gigeth.html#wp1078429

Robustness Variable
The robustness variable is a way of indicating how susceptible the subnet is to lost packets. IGMP can recover from robustness variable minus 1 lost IGMP packets. You can also click the scroll arrows to select a new setting. The robustness variable should be set to a value of 2 or greater. The default robustness variable value is 2.

Query Interval
The query interval is the amount of time in seconds between IGMP General Query messages sent by the router (if the router is the querier on this subnet). The default query interval is 125 seconds.

Query Response Interval
The query response interval is the maximum amount of time in seconds that the IGMP router waits to receive a response to a General Query message. The query response interval is the Maximum Response Time field in the IGMP v2 Host Membership Query message header. The default query response interval is 10 seconds and must be less than the query interval.

Last Member Query Interval
The last member query interval is the amount of time in seconds that the IGMP router waits to receive a response to a Group-Specific Query message. The last member query interval is also the amount of time in seconds between successive Group-Specific Query messages. The default last member query interval is 1 second.

Startup Query Interval
The startup query interval is the amount of time in seconds between successive General Query messages sent by a querier during startup. The default startup query interval is one-fourth of the value for the query interval.

Startup Query Count
The startup query count is the number of general query messages sent at startup. The default startup query count is 2.

Last Member Query Count
The last member query count is the number of Group-Specific Query messages sent before the router assumes that there are no members of the host group being queried on this interface. The default last member query count is 2.

Enable Automatic Recalculation of Defaults
Specifies whether the values in startup query interval, startup query count, and last member query count are calculated automatically based on the following:

• The startup query interval is one-fourth of the value for the query interval.
 
• The startup query count is the same value as the robustness variable.
 
• The last member query count is the same value as the robustness variable.
 
Group Membership Interval
The group membership interval is the number of seconds that must pass before a multicast router determines that there are no more members of a host group on a subnet. The group membership interval is calculated as the (robustness variable) * (query interval) + (query response interval). The group membership interval is a calculated value and is not configurable.

Other Querier Present Interval
The other querier present interval is the number of seconds that must pass before a multicast router determines that there is no other multicast router that takes precedence as the querier. The other querier present interval is the robustness variable multiplied by the query interval plus the query response interval divided by two. The other querier present interval is a calculated value and is not configurable.

Reference:
http://www.microsoft.com/technet/prodtechnol/windows2000serv/reskit/intwork/inaf_mul_nuid.mspx?pf=true