Multiple IP Performance & Redundancy Flashcards
What does Link Aggregation allow interfaces to do
Link Aggregation allows multiple network interfaces to combine into a single logical interface. This improves performance by increasing bandwidth and provides failover to maintain connection reliability.
Where is Link Aggregation used?
Data Centers: To connect servers to switches with higher throughput and reliability.
Enterprise Networks: For connecting switches or routers to improve performance and avoid downtime.
Storage Systems: In NAS or SAN setups to ensure fast and redundant data access.
What protocol controls Link Aggregation
LACP (Link Aggregation Control Protocol) controls Link Aggregation
What are the benefits of Link Aggregation
Provides benefits such as:
- increased bandwidth by combining multiple links,
- improved fault tolerance with automatic failover if one link fails
- efficient load balancing for optimized traffic distribution.
What is a limitation of Link Aggregation
it typically only works up to the nearest switch, meaning it cannot aggregate links across multiple switches unless specific technologies like MLAG (Multi-Chassis Link Aggregation) are used
What is VLAN used for
A VLAN (Virtual Local Area Network) is used to deliver multiple logically separated networks over a single physical cable
What are the benefits of VLAN
VLAN enables segmentation for security, performance, or organizational purposes
What identifies a VLAN in Ethernet frames
A VLAN is identified in Ethernet frames by a VLAN tag, which is a 12-bit identifier
What is the default behavior for untagged frames in VLANs
They are assigned a per-port default network
What are untagged ports in VLANs also known as
Access ports
What is the purpose of tagged ports in VLANs
To transmit and receive only tagged packets, allowing multiple VLANs to share a single physical connection between switches or routers
What is the security level of VLANs
The security level of VLANs is relatively weak, as it only provides logical separation.
Can compare it to marking private on an envelope
What is the benefit of combining Link Aggregation with VLANs
Provides resilience by ensuring failover and improved bandwidth for multiple VLANs, while also maintaining network separation and load balancing across links
What is the naive approach to load balancing
Treat all servers as one machine and rely on DNS round-robin
What is the role of a load balancer
To distribute incoming connections to the least loaded active server
What does a load balancer use to maintain session consistency
Source tracking for “sticky” connections
What does VRRP stand for
Virtual Router Redundancy Protocol
What does VRRP enable for routers and firewalls
Failover by advertising a shared IP address
What is the purpose of mutual monitoring in VRRP
To prevent split-brain scenarios during failover
What is anycasting in networking
Advertising the same IP address from multiple locations for redundancy
How does anycasting benefit DNS and CDNs
It provides load balancing and redundancy
What is a drawback of anycasting with TCP
New routes can disrupt long-lived connections
What are the key benefits of VLANs
Multiple logical networks on one physical infrastructure
What are the main benefits of Link Aggregation
Improved performance and faster failover
What is the purpose of load balancing
To share traffic among multiple systems behind a single IP
What is the goal of VRRP
To ensure service continuity through failover
What is the advantage of anycasting with UDP
It works well for short-lived connections
What is a tagged port in VLANs
One that transmits all packets with a VLAN tag
What is an untagged port in VLANs
One that strips or adds VLAN tags automatically
Why is VLAN security considered weak
It can be easily bypassed if the switch is compromised
What is the benefit of combining VLAN tagging and Link Aggregation
Delivering multiple networks over aggregated links
What does a load balancer do during a server failure
Redirects traffic to other active servers
What is the purpose of the PVID in VLANs
To assign untagged frames to a default VLAN
How does VRRP handle a failed router
Another router takes over the shared IP address
What does the term “router on a stick” refer to
Using a single router interface for multiple VLANs
What is the function of BGP in anycasting
To advertise routes to the same IP address from multiple locations
What is the main limitation of anycasting with TCP
It struggles with long-lived connections
What is the primary role of a load balancer in modern networking
To manage traffic and ensure efficient resource usage
How does anycasting improve redundancy
By routing traffic to the nearest available server
Why should VLANs not be used for hard security
They fail to provide strong separation assurances
What is the difference between tagged and untagged VLAN ports
Tagged ports transmit all packets with tags while untagged ports strip or add tags
What are the primary uses of anycasting
Handling DNS queries static web content and CDNs
What is the purpose of load balancing HTTP and HTTPS
To distribute requests while maintaining session consistency
What does VRRP provide for network devices
Failover for shared IP addresses
What is the purpose of stacked tags or Q-in-Q in VLANs
To allow VLANs within VLANs for complex setups
What is the main benefit of load balancers for web servers
They ensure even distribution of traffic and prevent overload
What is the primary use case for VRRP
Failover for critical services like DHCP or DNS
What is the impact of anycasting on DNS load balancing
It has largely replaced DNS-based load balancing
What is the main challenge of using anycasting for TCP-based services
Connection disruptions due to route changes
What are inbound NAT load balancers used for
Distributing connections among servers behind a single IP
What is the role of BGP in anycasting
To advertise the same IP from multiple locations
What is a potential issue with naive DNS round-robin load balancing
It provides uneven distribution and poor failure handling
What is the primary purpose of VLAN tags
To identify the network a frame belongs to
What does Link Aggregation achieve in network performance
It improves throughput and provides failover
What is the security limitation of VLANs
They rely on tags which can be manipulated
What is the difference between access and trunk ports in VLANs
Access ports are untagged while trunk ports carry multiple tagged VLANs
How does a load balancer detect server health
Through pings live connection counts or other metrics
What does VRRP do when a primary router fails
A secondary router takes over the shared IP address
What is a key advantage of anycasting
It reduces latency by routing to the closest server
What is a naive approach to implementing load balancing
Using DNS round-robin without considering server health
How do switches handle VLAN tagging
They add or strip tags based on configuration
What is a common design pattern involving VRRP
A pair of load balancers managing active-active backend servers
What is the purpose of Link Aggregation in modern networking
To provide redundancy and load balancing
Why is anycasting ideal for DNS
It routes queries to the nearest available server
What is the benefit of combining Link Aggregation and VLANs
Enhanced resilience with network separation
What is the function of a load balancer for HTTP and HTTPS traffic
To ensure session consistency while distributing requests
