1-2 - VPN Fundamentals Flashcards
Advantages of VPNs
- cost savings
- scalability
- improved security
- better performance
- flexibility and reliability
- greater access to mobile users
provider network
common infrastructure owned by service providers that are used to offer VPN services to customers
customer network
- exclusively under customer control
- consists of routers at various customer sites
- routers that connect the sites of individual customers to the service provider network are called customer edge routers
customer sites
sites that are contiguous parts of the customer network
P device
device on the provider network with no customer connectivity
PE device
device on provider network to which customer devices are connected
PE-CE link
the link between a PE router and a CE router
CE device
device in the customer network that links to the provider network (a.k.a. CPE)
VPN models
overlay: SP provided VCs between customer sites as a replacement for dedicated P2P links
peer-to-peer: SP actively participates in customer routing
Examples of Overlay VPNs (L2 and L3)
L2:
X.25
Frame Relay
ATM
L3:
GRE
DMVPN
IPsec
L2TPv3
SSL VPN
Peer-to-peer VPN examples
- ACLs (shared router)
- split routing (dedicated router)
- GET VPN
- MPLS VPN
Describe MPLS L2VPNs
- Enable the SP to offer P2P or MP2MP L2 connections between distant customer sites
- consolidate L2 traffic such as Ethernet, Frame Relay, ATM, HDLC, and PPP over an IP or MPLS network
- no IP signaling is needed between the customer and provider
Describe MPLS L3VPNs
- customer peers with the service provider at the IP Layer 3 level
- uses private, IP-based service offering from service provider
- they must establish IP routing (static or dynamic) to exchange routing info between customer sites that belong to the same VPN
- VRF instances isolate customer routing information
- MPLS seamlessly provides any-to-any connectivity between sites that belong to the same VPN
Intra-AS VPN
single ASN provides connectivity between sites that belong to a single company
Inter-AS VPN
- allows service providers that run separate networks to jointly offer MPLS VPN services to the same end customer
- can begin at one customer site and traverse multiple service provider backbones before it arrives at another customer site
What are the two basic VPN implementation models?
A. GET and MPLS
B. ACL and split routing
C. overlay and peer-to-peer
D. access and aggregation
C
