19 - Network Architecture Flashcards
What is Campus LAN?
LAN created to support devices in a building or multiple buildings in close proximity to one another
What are the three switch roles in Campus design?
Access
Distribution
Core
What is the function of Distribution switches in Campus design?
Aggregation point for access switches and to provide connectivity to the rest of the devices in the LAN
What is the function of Core switches in Campus design?
Aggregate distribution switches in very large campus LANs.
Provides very high forwarding rates for larger volumes of traffic
What is another name for Two-Tier Campus Design and why?
Collapsed core
Because there is no Core tier
What is Two-Tier Campus Design?
Most common campus LAN design Access and Distribution tiers Hybrid design - Star topology at Access layer - Partial Mesh at distribution layer
What is Three-Tier Campus Design
For very large Campus LANs, use of a Core tier in a partial mesh to interconnect the Distribution Tier provides very high forwarding rates while saving on switch ports and cables
Does a SOHO Wireless LAN AP utilize CAPWAP?
No, it doesn’t send frames to a WLC so doesn’t need to
What is PSE?
Power Sourcing Equipment
A device that supplies DC power over the Ethernet cable, typically a switch
What are PDs?
Powered Devices
Devices that can utilize PoE
How do PSE devices know that a given device can utilize PoE to prevent damage?
IEEE auto-negotiation messages
Low powered signals sent and monitor return signal to determine PoE power class
What is a Power Class?
For PoE a Power class determines how much power to supply a PD
What other two protocols can be used to Monitor for changes to power class aside from auto-negotiation?
CDP and LLDP
What is the IEEE standard for normal PoE and how many watts is it?
802.3af
15 watts
What is the IEEE standard for PoE+ and how many watts is it?
802.3at
30 watts
What is MetroE?
Metro Ethernet
A way of connecting different areas of a network together (possibly remote) to make them appear to be on the same network. The WAN service acts like a LAN switch
What is a PoP facility for MetroE?
A facility that is typically near to as many customer sites as possible that houses a device (usually switch) so that they can be connected to the customer device
What is an Access link with respect to MetroE?
A physical link between the customer and the SP where everything on the link falls within UNI
What is UNI?
User Network Interface
Everything on an Access link for MetroE
What key service does a MetroE SP promise?
To deliver Ethernet frames across the LAN (even to remote sites)
What is MEF?
Organization collaborating to define Metro Ethernet Standards
What are 3 key MEF Service types / topologies?
E-Line
E-LAN
E-Tree
What is an E-Line?
Ethernet Line Service
PTP EVC
Allows two customer devices to send Ethernet frames to each other as if they had a long crossover cable
What is another name for an E-Line?
Virtual Private Wire Service (VPWS)
What is an EVC?
Ethernet Virtual Connection
An association between two or more user network information that essentially forms a virtual connection between them / path across the network
What is needed to be used to have multiple E-Line services on a single access link?
802.1q trunking with a different VLAN ID for each E-Line service
What is E-LAN?
Ethernet LAN service
Several sites connected to WAN but with a goal of allowing every site to send frames directly to ever other site (full mesh)
As if Ethernet WAN service was one big Ethernet switch
What is E-Tree?
Hub and spoke design in which the central site can communicate directly with each remote site but they can only send to the central site
What is L3 E-Line?
PTP where both routers on each
What is MPLS?
Multiprotocol Label Switching VPN
A WAN service that routes IP packets between customer sites over the SPs network
How does MPLS work and identify traffic for different customers?
Devices in the MPLS network use Label Switching, with devices on the edge of the MPLS network adding and removing the label field inside the MPLS header when forwarding data across the network
What Layer service does MPLS provide to customers?
Layer 3
But really is a Layer 2.5 protocol because MPLS header is between L2 and L3
What is a big plus of MPLS being an L3 service with respect to data link protocols?
In theory any data link protocol could be used on MPLS access links
What must the SP be aware of with respect to the customer when using MPLS?
It must be aware of the customers IP addressing
What will the SPs MPLS network do with respect to the customers networks and routes?
- Build routing protocol neighbor relationships with customer routers
- Will learn customer subnets / routes with said protocols
- Will advertise customers routes to all routes a customer connects to the MPLS VPN can learn all routes as advertise through the network
True / False: MPLS encrypts data
False
What is a CE router in MPLS VPN networks?
Customer Edge router at customer site
Needs to learn routes from other CE routers, but does not form neighbor relationships directly with other CE routers, only with the PE router
What is the PE router in MPLS VPN networks?
Provider Edge router
True / False: MPLS networks advertise customers routes between PE routers
True
This is so that CE routers can learn ALL customer routes
What is Route re-distribution?
Taking routes from one routing protocol process and injecting them into another
Where is Route re-distribution performed?
In PE routers between routing protocols used by customer and internally
Does MPLS support QoS? If so, what is required?
Yes
Customer and SP must cooperate
What is DSLAM?
DSL Access Multiplexer
Splits analog and digital data
What do Site to Site VPNs generally use for security?
IPsec
How are IPsec VPNs realized in an enterprise?
GRE creates concept of tunnel, then apply IPsec to the tunnel
What IEEE Metro Ethernet standard does 100mbit/10kms?
100BASE-LX10
What IEEE Metro Ethernet standard does 1000mbit/5kms?
1000BASE-LX
What distance does 1000BASE-ZX support?
100km
What distances do IEEE LR standards support?
10km
What distances do IEEE ER standards support?
40km
What does a Hypervisor do?
Manages and allocates host hardware to each VM from a host machine
What is vNIC?
A virtual NIC that is part of a VM
How do VMs talk to each other?
Virtual Switch
How does a physical host network with a VM?
Its physical NIC interacts with the Virtual Switch
What is Cisco AVS?
Cisco Application Virtual Switch
What is a ToR switch?
Top of Rack Switch
What is an EoR switch?
End of Row Switch
What is the typical Physical data center network layout with respect to racks and rows?
- Each host in rack often cabled to 2 ToR switches
- Each ToR switch cabled to an EoR switch
What is the role of ToR and EoR switches in Physical data center network layouts?
Hosts cabled to 2 ToR switches to provide redundant paths into the LAN, acting as an access layer switch
EoR switches act as distribution switches
What is Cisco ACI?
Application Centric Infrastructure
What is Virtualized Data Center?
OS decoupled from the hardware where as a VM it can run on any server in the data center
Virtualization software and automatically start and move these VMs
What are the 5 NIST definitions for Cloud architecture?
- On Demand Self-service
- Broad network access
- Resource pooiling
- Rapid elasticity (pool appears to be unlimited)
- Measured service
What is a Cloud Service Catalog?
Web app listing anything that can be requested via the company’s cloud infrastructure
What is a Private Cloud?
On Premise service inside a company to internal customers that meets the NIST criteria
What is the key difference between IaaS and PaaS?
PaaS is more of a development platform, comes with the VM plus many more software tools beyond the basic OS
What is the downside of using the Internet as WAN connectivity to the public cloud?
- Less security
- Capacity can be an issue
- QoS
- No WAN SLA to all destinations of a network
What are some of the downsides of Private WANs?
- Install time
- Cost
- Migrating cloud providers is harder
True/False: WAN services like MPLS VPN and Ethernet WAN are preferable to an Internet VPN because they can provide QoS
True
What is a CSR?
Cloud Services Router
Router that runs as a VM in a cloud service
What is an Intercloud Exchange?
When a company (SP) creates a private network as a service.
It connects to multiple cloud providers on one side and other side connects to cloud consumers
What is one of key pros as a tradeoff for Intercloud Exchange?
It offers the benefits of private WAN (privacy etc) but also makes it easier to migrate to new cloud providers
What is a key downside of Intercloud Exchanges?
Another company is in the mix