2 Flashcards
What can cause broadcast radiation in a VM environment?
The Layer 2 domain can be large in virtual machine environments
Virtual machines communicate primarily through broadcast mode
What GRE features can you configure to prevent fragmentation?
TCP MSS
PMTUD
Which LISP device publishes EID-to-RLOC mappings?
ETR
What does ETR do?
Publishes EID-to-RLOC mappings for the site
Responds to Map-Request messages
Decapsulates and delivers LISP-encapsulated user data to end systems at the site
What are some benefits of using VMs to virtualize the server in a data center environment?
Reduce rack space, power, and cooling reqs
Faster deployment
What do route targets do in VRF-Lite?
Control the import and export of routes into a customer routing table
What is a PITR?
A LISP infrastructure device that provides connectivity between non-LISP sites and LISP sites
In what way is a Type 1 hypervisor more efficient than a Type 2 hypervisor?
Type 1 runs directly on the physical hardware of the host machine without relying on the underlying OS
What is VXLAN?
An encapsulation protocol that lets you overlay Layer 2 networks on top of Layer 3 networks
What is TCP MSS?
The maximum amount of data that a host is willing to accept in a single TCIP/IP datagram
Can be tuned to minimize fragmentation
How do you minimize fragmentation in IP and TCP?
TCP - MSS
IP - MTU
How do IP/MAC allocations work for VMs on Type 1 hypervisors?
Each VM needs a unique IP and MAC address to be able to reach other nodes
What are the two namespaces used in LISP?
EIDs - end hosts
RLOCs - devices that make up the global routing system
What are examples of Type 1 hypervisors?
Microsoft Hyper-V
VMware ESXi
Citrix XenServer
In LISP, what does the resolver do?
Accepts map requests
In LISP, what does the server do?
Learns EID mapping entries from an ETR
In LISP, what does the proxy ETR dp?
LISP to non-LISP
In LISP, what does the ITR do?
Receives packets from site-facing interfaces
What does VTEP do in VXLAN?
Encapsulates and de-encapsulates VXLAN Ethernet frames
What two actions provide controlled Layer 2 network connectivity between VMs running on the same hypervisor?
Using a virtual switch provided by the hypervisor
Using a virtual switch running as a separate VM
What is a type 1 hypervisor?
Runs directly on a physical server and has its own OS
What is the default keepalive value in GRE tunnels?
10 seconds
What is the default protocol/transport mode for a GRE tunnel?
GRE/IP
What is the purpose of the LISP routing and addressing architecture?
It creates two entries for each network node, one for its identity and another for its location on the network
What happens when a 1500-byte packet traverses a GRE tunnel?
The IP header is 20 bytes, GRE header is 4 bytes, so the 1500-byte packet will arrive fragmented
What maintains Layer 2 isolation between segments in a VXLAN environment?
VNID
What is VNID?
VXLAN Network Identifier
24-bit segment ID that defines the broadcast domain
What is a virtual machine?
An emulated machine with a dedicated compute, memory, storage resources, and a fully installed OS
What are some features of VSS?
Combines two devices
Supports devices that are geographically separated
Supported on Cisco 4500 and 6500
What are some features/limitations of switch stacking?
Limited in distance
Can have up to 9 switches
Supported in Cisco 2960, 3750, and 3850
What technology is used to provide segmentation for Layer 2 and 3 traffic in VXLAN?
VNI
How do you assign an IP address to a VRF?
ip address [add] [wildcard]
#address-family ipv4
Why might a tunnel be disabled after a network admin configures a GRE tunnel? %TUN-RECURDOWN
Recursive routing; the best path to the tunnel destination is through the tunnel itself
What is a benefit of using a Type 2 hypervisor instead of Type 1?
Can use hardware running other OSs
What’s true about crypto maps in tunneling configurations?
IPsec profiles do not need crypto maps
What is needed for a VM to run?
Hypervisor
Physical server hardware
What allocates computing resources for a VM?
Hypervisor
What component of a VM is responsible for sending packets to the hypervisor?
vNIC
What is the configuration file containing settings for a VM?
VMX
What is a zip file connecting a VM configuration file and virtual disk?
OVA
What is a file that contains a VM disk drive?
VMDK
What element enables communication between guest VMs within a virtualized environment?
vSwitch
