diff --git a/exporter/exporter.go b/exporter/exporter.go
index 0d6cfce..2694724 100644
--- a/exporter/exporter.go
+++ b/exporter/exporter.go
@@ -13,12 +13,8 @@ import (
 )
 
 var (
-	// Meta Monitoring Data, to be added to default /metrics
-
 	// Flow Data, to be exported on /flowdata
 	labels = []string{
-		// "src_port",
-		// "dst_port",
 		"router",
 		"ipversion",
 		"application",
@@ -79,17 +75,17 @@ func (e *Exporter) ServeEndpoints(addr string) {
 
 func (e *Exporter) Increment(flow *flow.FlowMessage) {
 	var application string
-	_, appGuess1 := filterPopularPorts(flow.GetSrcPort())
-	_, appGuess2 := filterPopularPorts(flow.GetDstPort())
-	if appGuess1 != "" {
-		application = appGuess1
-	} else if appGuess2 != "" {
-		application = appGuess2
+	if srcApp := filterPopularPorts(flow.GetSrcPort()); srcApp != "" {
+		application = srcApp
+	} else {
+		dstApp := filterPopularPorts(flow.GetDstPort())
+		application = dstApp
 	}
 
 	hflow := flow_helper.NewFlowHelper(flow)
 
 	peer := hflow.Peer()
+
 	var remoteAS string
 	if flow.GetFlowDirection() == 0 {
 		remoteAS = nameThatAS(flow.GetSrcAS())
@@ -98,8 +94,6 @@ func (e *Exporter) Increment(flow *flow.FlowMessage) {
 	}
 
 	labels := prometheus.Labels{
-		// "src_port":      fmt.Sprint(srcPort),
-		// "dst_port":      fmt.Sprint(dstPort),
 		"router":        net.IP(flow.GetSamplerAddress()).String(),
 		"ipversion":     hflow.IPVersionString(),
 		"application":   application,
@@ -111,8 +105,6 @@ func (e *Exporter) Increment(flow *flow.FlowMessage) {
 	}
 
 	e.kafkaMessageCount.Inc()
-	// flowNumber.With(labels).Add(float64(flow.GetSamplingRate()))
-	// flowPackets.With(labels).Add(float64(flow.GetPackets()))
 	e.flowBits.With(labels).Add(float64(flow.GetBytes()) * 8)
 }
 
@@ -124,124 +116,127 @@ func (e *Exporter) IncrementCtrl(topic string, partition int32, offset int64) {
 	e.kafkaOffsets.With(labels).Add(float64(offset))
 }
 
-func filterPopularPorts(port uint32) (uint32, string) {
+func filterPopularPorts(port uint32) string {
 	switch port {
 	case 80:
-		return port, "http"
+		return "http"
 	case 443:
-		return port, "https"
+		return "https"
 	case 20, 21:
-		return port, "ftp"
+		return "ftp"
 	case 22:
-		return port, "ssh"
+		return "ssh"
 	case 23:
-		return port, "telnet"
+		return "telnet"
 	case 53:
-		return port, "dns"
+		return "dns"
 	case 25, 465:
-		return port, "smtp"
+		return "smtp"
 	case 110, 995:
-		return port, "pop3"
+		return "pop3"
 	case 143, 993:
-		return port, "imap"
+		return "imap"
 	}
-	return 0, ""
+	return ""
+}
+
+// Putting asnmap outside the nameThatAS function prevents recreating that map every
+// time that function is called.
+// As of Go 1.16 the compiler is not smart enough to do that optimization itself.
+var asnmap = map[uint32]string{
+	43:     "Brookhaven National Laboratory",
+	70:     "National Library Medicine USA",
+	174:    "Cogent",
+	513:    "CERN",
+	559:    "SWITCH",
+	680:    "DFN",
+	702:    "Verizon",
+	714:    "Apple",
+	786:    "JANET",
+	1239:   "Sprint",
+	1273:   "Vodafone",
+	1297:   "CERN",
+	1299:   "Telia",
+	1754:   "DESY",
+	2018:   "AFRINIC",
+	2603:   "NORDUnet",
+	2906:   "Netflix",
+	2914:   "NTT",
+	3209:   "Vodafone",
+	3257:   "GTT",
+	3303:   "Swisscom",
+	3320:   "Deutsche Telekom",
+	3356:   "CenturyLink",
+	4356:   "Epic Games",
+	5430:   "freenet",
+	5501:   "Fraunhofer",
+	5511:   "Orange",
+	6185:   "Apple",
+	6453:   "TATA",
+	6507:   "Riot Games",
+	6724:   "Strato",
+	6735:   "sdt.net",
+	6805:   "Telefonica",
+	6830:   "Vodafone",
+	6939:   "Hurricane Electric",
+	7018:   "AT&T",
+	8068:   "Microsoft",
+	8075:   "Microsoft",
+	8220:   "Colt",
+	8403:   "Spotify",
+	8560:   "1&1",
+	8674:   "Netnod",
+	8763:   "DENIC",
+	8881:   "Versatel",
+	9009:   "GLOBALAXS",
+	10310:  "Yahoo",
+	13030:  "Init7",
+	13335:  "Cloudflare",
+	15133:  "Verizon",
+	15169:  "Google",
+	16276:  "OVH",
+	16509:  "Amazon",
+	16591:  "Google Fiber",
+	16625:  "Akamai",
+	19679:  "Dropbox",
+	20446:  "Highwinds",
+	20504:  "RTL",
+	20677:  "imos",
+	20940:  "Akamai",
+	22822:  "Limelight",
+	24429:  "Alibaba",
+	24940:  "Hetzner",
+	30361:  "Swiftwill",
+	31334:  "Kabel Deutschland",
+	32590:  "Valve Steam",
+	32934:  "Facebook",
+	33915:  "Vodafone",
+	35402:  "ecotel",
+	36459:  "Github",
+	36561:  "Google",
+	37963:  "Alibaba",
+	39702:  "S-IT",
+	41552:  "Ebay",
+	41690:  "Dailymotion",
+	46489:  "Twitch",
+	48918:  "Globalways",
+	54113:  "Fastly",
+	54994:  "QUANTIL",
+	57976:  "Blizzard",
+	58069:  "KIT",
+	60781:  "Leaseweb",
+	61339:  "LHC",
+	197540: "Netcup",
+	197602: "TV-9",
+	206339: "Schuler Pressen",
 }
 
 func nameThatAS(asn uint32) string {
-	asnmap := map[uint32]string{
-		43:     "Brookhaven National Laboratory",
-		70:     "National Library Medicine USA",
-		174:    "Cogent",
-		513:    "CERN",
-		559:    "SWITCH",
-		680:    "DFN",
-		702:    "Verizon",
-		714:    "Apple",
-		786:    "JANET",
-		1239:   "Sprint",
-		1273:   "Vodafone",
-		1297:   "CERN",
-		1299:   "Telia",
-		1754:   "DESY",
-		2018:   "AFRINIC",
-		2603:   "NORDUnet",
-		2906:   "Netflix",
-		2914:   "NTT",
-		3209:   "Vodafone",
-		3257:   "GTT",
-		3303:   "Swisscom",
-		3320:   "Deutsche Telekom",
-		3356:   "CenturyLink",
-		4356:   "Epic Games",
-		5430:   "freenet",
-		5501:   "Fraunhofer",
-		5511:   "Orange",
-		6185:   "Apple",
-		6453:   "TATA",
-		6507:   "Riot Games",
-		6724:   "Strato",
-		6735:   "sdt.net",
-		6805:   "Telefonica",
-		6830:   "Vodafone",
-		6939:   "Hurricane Electric",
-		7018:   "AT&T",
-		8068:   "Microsoft",
-		8075:   "Microsoft",
-		8220:   "Colt",
-		8403:   "Spotify",
-		8560:   "1&1",
-		8674:   "Netnod",
-		8763:   "DENIC",
-		8881:   "Versatel",
-		9009:   "GLOBALAXS",
-		10310:  "Yahoo",
-		13030:  "Init7",
-		13335:  "Cloudflare",
-		15133:  "Verizon",
-		15169:  "Google",
-		16276:  "OVH",
-		16509:  "Amazon",
-		16591:  "Google Fiber",
-		16625:  "Akamai",
-		19679:  "Dropbox",
-		20446:  "Highwinds",
-		20504:  "RTL",
-		20677:  "imos",
-		20940:  "Akamai",
-		22822:  "Limelight",
-		24429:  "Alibaba",
-		24940:  "Hetzner",
-		30361:  "Swiftwill",
-		31334:  "Kabel Deutschland",
-		32590:  "Valve Steam",
-		32934:  "Facebook",
-		33915:  "Vodafone",
-		35402:  "ecotel",
-		36459:  "Github",
-		36561:  "Google",
-		37963:  "Alibaba",
-		39702:  "S-IT",
-		41552:  "Ebay",
-		41690:  "Dailymotion",
-		46489:  "Twitch",
-		48918:  "Globalways",
-		54113:  "Fastly",
-		54994:  "QUANTIL",
-		57976:  "Blizzard",
-		58069:  "KIT",
-		60781:  "Leaseweb",
-		61339:  "LHC",
-		197540: "Netcup",
-		197602: "TV-9",
-		206339: "Schuler Pressen",
-	}
 	if name, ok := asnmap[asn]; ok {
 		return name
+	} else if asn == 0 {
+		return "unset"
 	} else {
-		if asn == 0 {
-			return "unset"
-		}
 		return "other"
 	}
 }