Intermediate System to Intermediate System is a routing protocol designed to move information efficiently within a computer network, a group of physically connected computers or similar devices. It accomplishes this by determining the best route for data through a Packet switching network; the IS-IS protocol is defined in ISO/IEC 10589:2002 as an international standard within the Open Systems Interconnection reference design. The Internet Engineering Task Force republished IS-IS in RFC 1142, but that RFC was marked as "historic" by RFC 7142 because it republished a draft rather than a final version of the ISO standard, causing confusion. IS-IS has been called "the de facto standard for large service provider network backbones." IS-IS is an interior gateway protocol, designed for use within network. This is in contrast to exterior gateway protocols Border Gateway Protocol, used for routing between autonomous systems. IS-IS is a link-state routing protocol, operating by reliably flooding link state information throughout a network of routers.

Each IS-IS router independently builds a database of the network's topology, aggregating the flooded network information. Like the OSPF protocol, IS-IS uses Dijkstra's algorithm for computing the best path through the network. Packets are forwarded, based on the computed ideal path, through the network to the destination; the IS-IS protocol was developed by a team of people working at Digital Equipment Corporation as part of DECnet Phase V. It was standardized by the ISO in 1992 as ISO 10589 for communication between network devices that are termed Intermediate Systems by the ISO; the purpose of IS-IS was to make possible the routing of datagrams using the ISO-developed OSI protocol stack called CLNS. IS-IS was developed at the same time that the Internet Engineering Task Force IETF was developing a similar protocol called OSPF. IS-IS was extended to support routing of datagrams in the Internet Protocol, the Network Layer protocol of the global Internet; this version of the IS-IS routing protocol was called Integrated IS-IS IS-IS adjacency can be either broadcast or point-to-point.

Hello Packet: The IS-IS hello packets needs to be exchanged periodically between 2 routers to establish adjacency. Based on the negotiation, one of them will be selected as DIS; this hello packet will be sent separately for Level-1 or Level-2. LSP: This contains the actual route information; this LSP can contain many type-length-values. CSNP: This packet will be sent only by the DIS. By default for every 10 seconds, CSNP packet will be transmitted by DIS; this will contain the list of LSP ID's along with sequence checksum. PSNP: If the router which receives CSNP packet finds some discrepancy in its own database, it will send an PSNP request asking the DIS to send specific LSP back to it. Both IS-IS and Open Shortest Path First are link state protocols, both use the same Dijkstra algorithm for computing the best path through the network; as a result, they are conceptually similar. Both support variable length subnet masks, can use multicast to discover neighboring routers using hello packets, can support authentication of routing updates.

While OSPF was natively built to route IP and is itself a Layer 3 protocol that runs on top of IP, IS-IS is an OSI Layer 2 protocol. It is at the same layer as Connectionless Network Protocol; the widespread adoption of IP may have contributed to OSPF's popularity. IS-IS does not use IP to carry routing information messages. OSPF version 2, on the other hand, was designed for IPv4. IS-IS is neutral regarding the type of network addresses; this allowed IS-IS to be used to support IPv6. To operate with IPv6 networks, the OSPF protocol was rewritten in OSPF v3. Both OSPF and IS-IS routers build a topological representation of the network; this map indicates the subnets which each IS-IS router can reach, the lowest-cost path to a subnet is used to forward traffic. IS-IS differs from OSPF in the way that "areas" are routed between. IS-IS routers are designated as being: Level 1. Routing information is exchanged between Level 1 routers and other Level 1 routers of the same area, Level 2 routers can only form relationships and exchange information with other Level 2 routers.

Level 1–2 routers exchange information with both levels and are used to connect the inter area routers with the intra area routers. In OSPF, areas are delineated on the interface such that an area border router is in two or more areas at once creating the borders between areas inside the ABR, whereas in IS-IS area borders are in between routers, designated as Level 2 or Level 1–2; the result is that an IS-IS router is only a part of a single area. IS-IS does not require Area 0 to be the backbone area through which all inter-area traffic must pass; the logical view is that OSPF creates something of a spider web or star topology of many areas all attached directly to Area Zero and IS-IS by contrast creates a logical topology of a backbone of Level 2 routers with branches of Level 1–2 and Level 1 routers forming the individual areas. IS-IS differs from OSPF in the methods by which it reliably floods topology and topology change information through the network. However, the basic concepts are similar.

OSPF has a larger set of optional features specified in the protocol standards. However IS-IS is easier to expand: its use of type-length-value data allows engineers to implement support for new techniques wi

Looty Pijamini

Looty Pijamini is an Inuit artist. He works in Grise Fiord, Nunavut. Pijamini was born November 14, 1953, in Clyde River and moved to Grise Fiord in 1961, when his father, a special constable in the Royal Canadian Mounted Police was posted there. Along with Simeonie Amagoalik in Resolute, Pijamini was commissioned by the Canadian government to build a monument to the High Arctic relocation which took place in 1955. Pijamini's monument, located in Grise Fiord, depicts a woman with a young boy and a husky, with the woman somberly looking out towards the ocean. Pijamini said that he intentionally made them look melancholy because the relocation was not a happy event; the monument was unveiled in September 2010, received praise from the Canadian Broadcasting Corporation

El Quartelejo Ruins

El Quartelejo, or El Cuartelejo, is the name given to the archeological remains of the northernmost Indian pueblo and the only known pueblo in Kansas. Located in Lake Scott State Park, the remains of the stone and adobe pueblo are situated north of Scott City, Kansas, on Ladder Creek; the origin of El Quartelejo has two possibilities. In 1664 a group of Pueblo Indians left New Mexico and were rounded up and brought back by the Spanish, they may have constructed El Quartelejo. It is more that, after the collapse of the Pueblo Revolt, the Spanish reconquered New Mexican pueblos, one group of Taos and Picuris people fled the area in 1696, they searched for a new home among the Plains Apache on the Great Plains. For ten years, the fleeing Taos and Picuris Pueblo people evaded the Spanish. During those years, the French attempted to trade with the Cuartelejo Apaches. In 1706 the Pueblos were forced back to New Mexico; when the Pueblo Indians were seized, the Spanish commander Juan de Ulibarrí wrote that they were dwelling in permanent structures.

The Spanish called this settlement El Quartelejo, the region around it was called San Luis Province. No American Indians lived in El Quartelejo after 1706, but Spanish and French occupied the structure as a frontier outpost during the 18th century; the ill-fated, Spanish Villasur expedition of 1720 stopped at El Cuartelejo on its way north to investigate the extent of French influence. Near the forks of the Platte River, the Pawnees and Otoes killed most of the party under French direction. By the 1730s raids by Comanche and Pawnee had decimated the Cuartelejo Apache; the survivors moved south to join the Jicarilla Apache at Pecos. However, after 1763 and the French retreat from the area, the pueblo was abandoned with only a mound and a few irrigation ditches remaining, its walls decayed and the structure was buried by drifting soil. The pueblo in 1898 archeologists rediscovered El Quartelejo. Since the site has been excavated to reveal that the pueblo was a seven-room structure, enough to house a small band of Indians.

Near the pueblo are traces of shallow ditches extending from the nearby springs. These ditches were most used to irrigate crops in nearby fields. Near here in 1878, Col. William H. Lewis, commanding troops from Fort Dodge, was fatally wounded in a battle with chief Dull Knife and his Northern Cheyennes. Lewis was the last army officer killed by Indians in Kansas. In 1964, the El Quartelejo ruins were designated a National Historic Landmark, the area is now part of Lake Scott State Park; the Scott Lake site was developed in 1971 as an interpretive exhibit by Kansas Historical Society archeologists. The outline of the ruins was restored and markers placed for park visitors to see. Since 2004, the National Park Service has listed the El Quartelejo site as "at risk" because of ongoing weather-related deterioration to the ruins. El Quartelejo Museum in Scott City is operated by the Scott County Historical Society; the free museum focuses from prehistory to the present day. Temporary exhibitions highlight contemporary arts or culture.

The Spanish spelling of El Quartelejo is with a “C”: El Cuartelejo. The English spelling is with a “Q”: El Quartelejo, they are used interchangeablely at the museum and the park. El Quartelejo Museum - Local museum named after the ruins El Cuartelejo – “The Home Far Away” Text of highway historical marker