Network Structure Models - CCDA 640-864 - page 63

Cisco supports Multilink Point-to-Point Protocol (MPPP), which is an Internet Engineer-
ing Task Force (IETF) standard for ISDN B-channel (or asynchronous serial interface) ag-
gregation. It bonds multiple WAN links into a single logical channel. MPPP is defined in
RFC 1990. MPPP does not specify how a router should accomplish the decision-making
process to bring up extra channels. Instead, it seeks to ensure that packets arrive in se-
quence at the receiving router. Then, the data is encapsulated within PPP and the datagram
is given a sequence number. At the receiving router, PPP uses this sequence number to re-
create the original data stream. Multiple channels appear as one logical link to upper-layer
protocols. For Frame Relay networks, FRF.16.1 Multilink Frame Relay is used to perform
the similar function.

Ta ble 2 - 4 summarizes the four main redundancy models.

Ta b l e 2 - 4 Redundancy Models

Redundancy Type Description

Wo r k s t a t i o n t o r o u t e r r e -
dundancy

Use of HSRP, VRRP, and VSS

Server redundancy Uses dual-attached NICs, FEC, or GEC port bundles

Route redundancy Provides load balancing and high availability

Link redundancy Use of multiple WAN links that provide primary and secondary

failover for higher availability

References and Recommended Reading
Cisco Enterprise Teleworker Solution. www.cisco.com/en/US/netsol/ns340/ns394/ns430/
networking_solutions_packages_list.html .

Enterprise Architectures. www.cisco.com/en/US/netsol/ns517/
networking_solutions_market_segment_solutions_home.html .

Cisco Enterprise Solutions Portal. www.cisco.com/en/US/netsol/ns340/networking_
solutions_large_enterprise_home.html .

Borderless Networks Solutions. www.cisco.com/en/US/netsol/ns1016/index.html.

Borderless Networks Architecture. www.cisco.com/en/US/netsol/ns1015/architecture.html.

Cisco TrustSec. www.cisco.com/en/US/solutions/collateral/ns170/ns896/ns1051/
at_a_glance_c45-577269.pdf .

Medianet at a Glance. www.cisco.com/web/solutions/medianet/docs/C45-511997-00me-
dialnet_aag120308.pdf .

Application Performance white paper. www.cisco.com/en/US/solutions/ns1015/
lippis_white_paper_application_velocity.pd .

RFC 3758. Virtual Router Redundancy Protocol (VRRP).

RFC 1990. The PPP Multilink Protocol (MP).

ps9336/prod_qas0900aecd806ed74b.html .